Black screen after login is a GNOME problem, which is caused by trying to remote in as a user that is logged into the desktop already. I solved this by creating an additional user. It was intensely annoying.

It's not just a GNOME issue; it happens with KDE, and I think basically any common desktop environment (although my own experience over the past several years is mainly with those two).

There are workarounds, but they are "not recommended" for reasons I forget. (I don't mean the workaround of creating a separate user; that is the recommended "solution" but it doesn't solve the problem of "I need to log into this user's active session" which is probably about half of the total use cases for remote desktop in general.)

The "Permission issues / strange password prompts" is generally polkit (formerly PolicyKit), which annihilates the user experience when coming in over RDP; the famous c-energy script referenced in the parent solves a few of those issues, but not nearly all of them. You should expect errors when you try to adjust display properties, try to use any app that looks at disks/partitions, any app that does anything wrt Wi-Fi or Ethernet settings, any app that deals with VMs in any way, and like 357 other things. Each one can be solved by googling for 1-2 hours and then writing some arcane PolKit config file, but it ends up taking about as much time as designing and building a bear-proof suit of armor from scratch, and then testing it against several live bears.