What finally fixed this for me was:
1) deleting the user in unraid
2) create a new temporary user
3) give that account access to the smb shares
4) verify it worked in windows (it worked for me)
5) delete that temporary user
6) reboot the windows pc
7) recreate the account in unraid, give permissions, and bam, success!
All of my shares are set to private.
I don't know how much of it was necessary, or if it'll work for others, but i've finally got access to the shares again. It was an Unraid issue for me, as multiple windows PCs were having issues.