It was not automatially removed during update from 6.12.6 to 6.12.8 in my case. The System update even automatically updated the realtek driver plugin to a version compatible to 6.12.8 before applying the system upgrade itself.
I' using a RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet Controller (rev 15) - no hickups so far
I just started with Unraid 6.12.6 and generated users and for each user a share with the name of the share identical to the <username> of each user.
Additionally I generated a share called "homes" (with s).
Then i connected on my Windows machine to \\<SERVERIP>\homes and i was surprisingly connected with my own <username> share. This looked on the beginning very strange to me but is possibly the "inbuilt" solution which the users in this thread were looking for. I am sure that I was connected with my own "username" share because there was already data stored while the share "homes" which I manually generated was still empty.
So I made the share "homes" invisible for SMB again and was still able to connect from my Windows machine to \\<SERVERIP>\homes but again I was connected with my own share <username>.
to summarize:
1.) generate for every username one usershare and use exactly the same name for share and username
2.) each user connects via SMB to \\SERVERNAME\homes and each user will be connected to it's own share
that's it.
Unfortunately this feature (or bug?) seems not to be found in the official UNRAID documentation. I searched for "homes" and found nothing explainting this observed behaviour