diff --git a/src/ol/Feature.js b/src/ol/Feature.js
index 4bfb5401de..4ab77b4393 100644
--- a/src/ol/Feature.js
+++ b/src/ol/Feature.js
@@ -11,7 +11,7 @@ import {listen, unlistenByKey} from './events.js';
  */
 
 /**
- * @typedef {Feature<import("./geom/Geometry.js").default>|import("./render/Feature.js").default} FeatureLike
+ * @typedef {Feature|import("./render/Feature.js").default} FeatureLike
  */
 
 /***
@@ -70,7 +70,7 @@ import {listen, unlistenByKey} from './events.js';
  * ```
  *
  * @api
- * @template {import("./geom/Geometry.js").default} Geometry
+ * @template {import("./geom/Geometry.js").default} [Geometry=import("./geom/Geometry.js").default]
  */
 class Feature extends BaseObject {
   /**
diff --git a/src/ol/format/KML.js b/src/ol/format/KML.js
index 993e14196b..4c87601b00 100644
--- a/src/ol/format/KML.js
+++ b/src/ol/format/KML.js
@@ -1007,8 +1007,7 @@ function createFeatureStyleFunction(
       if (drawName) {
         const geometry = feature.getGeometry();
         if (geometry) {
-          const type = geometry.getType();
-          if (type === GeometryType.GEOMETRY_COLLECTION) {
+          if (geometry instanceof GeometryCollection) {
             multiGeometryPoints = geometry
               .getGeometriesArrayRecursive()
               .filter(function (geometry) {
@@ -1020,6 +1019,7 @@ function createFeatureStyleFunction(
               });
             drawName = multiGeometryPoints.length > 0;
           } else {
+            const type = geometry.getType();
             drawName =
               type === GeometryType.POINT || type === GeometryType.MULTI_POINT;
           }
diff --git a/src/ol/format/Polyline.js b/src/ol/format/Polyline.js
index f0c9ae1820..b87c162be1 100644
--- a/src/ol/format/Polyline.js
+++ b/src/ol/format/Polyline.js
@@ -110,7 +110,7 @@ class Polyline extends TextFeature {
   }
 
   /**
-   * @param {import("../Feature.js").default} feature Features.
+   * @param {import("../Feature.js").default<LineString>} feature Features.
    * @param {import("./Feature.js").WriteOptions} [opt_options] Write options.
    * @protected
    * @return {string} Text.
@@ -126,7 +126,7 @@ class Polyline extends TextFeature {
   }
 
   /**
-   * @param {Array<import("../Feature.js").default>} features Features.
+   * @param {Array<import("../Feature.js").default<LineString>>} features Features.
    * @param {import("./Feature.js").WriteOptions} [opt_options] Write options.
    * @protected
    * @return {string} Text.
diff --git a/src/ol/interaction/Draw.js b/src/ol/interaction/Draw.js
index f01e3e1a9c..64c7be6c98 100644
--- a/src/ol/interaction/Draw.js
+++ b/src/ol/interaction/Draw.js
@@ -421,7 +421,7 @@ class Draw extends PointerInteraction {
 
     /**
      * Sketch feature.
-     * @type {Feature}
+     * @type {Feature<import('../geom/SimpleGeometry.js').default>}
      * @private
      */
     this.sketchFeature_ = null;
@@ -1022,7 +1022,7 @@ class Draw extends PointerInteraction {
 
   /**
    * Stop drawing without adding the sketch feature to the target layer.
-   * @return {Feature} The sketch feature (or null if none).
+   * @return {Feature<import("../geom/SimpleGeometry.js").default>} The sketch feature (or null if none).
    * @private
    */
   abortDrawing_() {
diff --git a/src/ol/interaction/Modify.js b/src/ol/interaction/Modify.js
index 0807ea0da4..ebd4aba6c6 100644
--- a/src/ol/interaction/Modify.js
+++ b/src/ol/interaction/Modify.js
@@ -253,7 +253,7 @@ class Modify extends PointerInteraction {
 
     /**
      * Editing vertex.
-     * @type {Feature}
+     * @type {Feature<Point>}
      * @private
      */
     this.vertexFeature_ = null;
diff --git a/src/ol/layer/Layer.js b/src/ol/layer/Layer.js
index 87dce260ca..0c55fdc460 100644
--- a/src/ol/layer/Layer.js
+++ b/src/ol/layer/Layer.js
@@ -25,7 +25,7 @@ import {listen, unlistenByKey} from '../events.js';
  */
 
 /**
- * @template {import("../source/Source.js").default} SourceType
+ * @template {import("../source/Source.js").default} [SourceType=import("../source/Source.js").default]
  * @typedef {Object} Options
  * @property {string} [className='ol-layer'] A CSS class name to set to the layer element.
  * @property {number} [opacity=1] Opacity (0, 1).
@@ -93,8 +93,8 @@ import {listen, unlistenByKey} from '../events.js';
  * @fires import("../render/Event.js").RenderEvent#prerender
  * @fires import("../render/Event.js").RenderEvent#postrender
  *
- * @template {import("../source/Source.js").default} SourceType
- * @template {import("../renderer/Layer.js").default} RendererType
+ * @template {import("../source/Source.js").default} [SourceType=import("../source/Source.js").default]
+ * @template {import("../renderer/Layer.js").default} [RendererType=import("../renderer/Layer.js").default]
  * @api
  */
 class Layer extends BaseLayer {
diff --git a/src/ol/renderer/webgl/TileLayer.js b/src/ol/renderer/webgl/TileLayer.js
index 2af3a33b3d..efce2e56cb 100644
--- a/src/ol/renderer/webgl/TileLayer.js
+++ b/src/ol/renderer/webgl/TileLayer.js
@@ -96,8 +96,9 @@ function getRenderExtent(frameState, extent) {
       fromUserExtent(layerState.extent, frameState.viewState.projection)
     );
   }
-  const source =
-    /** {import("../../source/Tile.js").default} */ layerState.layer.getRenderSource();
+  const source = /** @type {import("../../source/Tile.js").default} */ (
+    layerState.layer.getRenderSource()
+  );
   if (!source.getWrapX()) {
     const gridExtent = source
       .getTileGridForProjection(frameState.viewState.projection)
diff --git a/src/ol/source/Cluster.js b/src/ol/source/Cluster.js
index 66fc33e4fe..5621a33d7f 100644
--- a/src/ol/source/Cluster.js
+++ b/src/ol/source/Cluster.js
@@ -115,7 +115,7 @@ class Cluster extends VectorSource {
     this.geometryFunction =
       options.geometryFunction ||
       function (feature) {
-        const geometry = feature.getGeometry();
+        const geometry = /** @type {Point} */ (feature.getGeometry());
         assert(geometry.getType() == GeometryType.POINT, 10); // The default `geometryFunction` can only handle `Point` geometries
         return geometry;
       };
diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index 32d6cf6644..77f4f61bd8 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -34,7 +34,7 @@ import {xhr} from '../featureloader.js';
  * @classdesc
  * Events emitted by {@link module:ol/source/Vector} instances are instances of this
  * type.
- * @template {import("../geom/Geometry.js").default} Geometry
+ * @template {import("../geom/Geometry.js").default} [Geometry=import("../geom/Geometry.js").default]
  */
 export class VectorSourceEvent extends Event {
   /**
@@ -170,7 +170,7 @@ export class VectorSourceEvent extends Event {
  *
  * @fires VectorSourceEvent
  * @api
- * @template {import("../geom/Geometry.js").default} Geometry
+ * @template {import("../geom/Geometry.js").default} [Geometry=import("../geom/Geometry.js").default]
  */
 class VectorSource extends Source {
   /**
@@ -299,9 +299,15 @@ class VectorSource extends Source {
 
     let collection, features;
     if (Array.isArray(options.features)) {
-      features = options.features;
+      features =
+        /** @type {Array<import("../Feature.js").default<Geometry>>} */ (
+          options.features
+        );
     } else if (options.features) {
-      collection = options.features;
+      collection =
+        /** @type {Collection<import("../Feature.js").default<Geometry>>} */ (
+          options.features
+        );
       features = collection.getArray();
     }
     if (!useSpatialIndex && collection === undefined) {