How do I cast mongodb's _ids from string to ObjectId?

Question

On the frontend I compile a collection of bookmark ids to be deleted as seen in the following function:

public deleteBookmarks = (siteId) => {
    const siteForBookmarkDelete = this.category?.sites.find(s1 => s1.site._id === siteId)

    const bookmarksForDelete = siteForBookmarkDelete.site.bookmarks
      .filter(bookmark => bookmark.checked === true)

    const bookmarkIds = [];

    for(let bm of bookmarksForDelete) {
      bookmarkIds.push(bm._id)
    }

    this.categoriesService.deleteBookmark(this.category?._id, siteId, bookmarkIds )

 }

On the backend, I tried to delete the bookmarks with the condition:

...
{
       $pull: {
           bookmarks: {
               _id: {$in: bookmarkIds}
           }
       }
   })

I get the error:

CastError: Cast to ObjectId failed for value "63bd8916abbd6f490b568121,63bd8918abbd6f490b56812a" (type string) at path "_id" because of "BSONTypeError"
at model.Query.exec

I interpret this to mean even though I put actual ObjectIds on the array, they were converted to strings so I modified my backend code to convert each _id on the array to ObjectId.

const mongoose = require('mongoose')
const { ObjectId} = mongoose.Schema.Types;


  exports.deleteBookmarks = async (req, res) => {
   const {categoryId, siteId, bookmarkIds} = req.params;

   const objectIds = [ObjectId];

   for(let bmId of bookmarkIds) {
      objectIds.push(ObjectId(bmId))
   }

   try {
       const site = await Sites.findOneAndUpdate({
          _id: siteId,
          categoryId
      }, 
   {
       $pull: {
           bookmarks: {
               _id: {$in: objectIds}
           }
       }
   })

    getAllCategories(req, res);
  } catch(error) {
      console.error(error);
      return res.status(500).send('Error adding bookmark.')    
  }


  }

Then I get this error:

\node_modules\mongoose\lib\schematype.js:43
this[schemaTypeSymbol] = true; ^
TypeError: Cannot set properties of undefined (setting 'Symbol(mongoose#schemaType)')
at SchemaType

I am thinking this ObjectId may be the wrong one to use but the documentation doesn't show what package it is getting its ObjectId from.

const { ObjectId} = mongoose.Schema.Types;