Issues with two Apple ID on one macbook

I have two accounts on my macbook with separate Apple IDs. Both are my won accounts, but one's for work.

Both accounts carry the same name (obviously), but have different avatars. From my personal account, using Family sharing, I have invited my work's account to be able to share some iCloud folders.

The following issues has now arisen:

• In the list of Family members, the work account (the one on the top) has got the same avatar as my personal account's (the exact same can be seen in my iPhone). It also has the same name, even after I changed the name in my work's Apple ID and removed and added the ID. And in my work account, it is exactly the other way around: there I see my work's avatar twice.

• It won't let me share iCloud folders. I can send the invite and receive it in my work mail, but then it says "The owner has stopped sharing". I have shared folders before (that is, before Sonoma and before my current macbook) and those I can access in my work account.

So the Q's are:

• how can Sonoma think that it should use my personal avatar for my work family member, only because we have the same name and are on the same computer?
• how do I manage to share folders again?