A few of our users are sporadically unable to share their screen or view shared screen in Teams

Symptom: On a video or audio call a user shares their screen but the participants just see their profile picture. When another participant shares their screen everyone can see except the user in question. This is happening to at least two of our users.

Things we have tried:

1. Clearing Teams cache (deleting folders from the %Appdata% folder

2. Updating to latest version

3. Complete uninstall/reinstall

4. Windows fully up to date

5. All drivers fully up to date

6. Made sure the applied policy in Admin Centre is the same for everyone (Global Org default, screen share available for internal and external users)

7. Approximately 3 million restarts of the machine

8. Disabled hardware 3d acceleration

9. Checked local privacy settings for meetings

This only happens maybe 1 out of every 3 times but it's still unacceptable for the users in question. I can see that there are a number of other reports of this but no solution, other than to turn off the "New meeting experience" which isn't even available as an option anymore...

Any other troubleshooting steps available for this?