P: "Containing keywords no longer sent to Adobe Stock".

This is happening because LR 11 preserves the order of keywords you send to Adobe Stock (sometimes -- the feature is poorly designed and very fragile, but that's another story).  It does this not by actually setting the order of the keywords in the industry-standard metadata fields, but rather by adding a new Adobe-specific field XMP:WeightedFlatSubject.  This new field only contains leaf keywords, not ancestor keywords.

For example, if you assign the keyword A > B > C to a photo and export it, here are the contents of the relevant metadata fields:

[IPTC] Keywords              : A, B, C
[XMP]  Subject               : A, B, C
[XMP]  Hierarchical Subject  : A|B|C
[XMP]  Weighted Flat Subject : C

Note that the other fields contain A, B, and C, but XMP:WeightedFlatSubject just contains the leaf keyword C.  When that field is present, Adobe Stock uses it in preference to the other keyword fields.

If you delete XMP:WeightedFlatSubject before uploading to Adobe Stock, then Adobe Stock will import all three keywords A, B, and C.  You could do that manually by exporting to your local disk, using Exiftool to delete that field, then uploading to Adobe Stock.

Or you could use the Metadata Wrangler plugin in concert with the Adobe Stock plugin to remove that field automatically on every export to Adobe Stock.  

Of course deleting XMP:WeightedFlatSubject will forgo the ability to set a specific keyword order within LR.  But that feature is so fragile and difficult to use I bet most Adobe Stock users don't use it:

https://community.adobe.com/t5/lightroom-classic-ideas/p-custom-sort-order-of-keywords-instead-of-alphabetic/idc-p/12526371#M13291