The Pi SOC have a hardware watchdog.
I setup years ago and did some testing.
I believe it is now enabled by default, but can be customised to perform specific tasks.
You can also build a function in your code to "kick the watchdog" to overcome specific app lockup issues.
It has been years ...
As per microsoft implementation you can take only one RDP session at a time. If you want to use more than one RDP session then you need to check the Terminal Service under Windows Server where it requires configuring an Windows Server with CAL license which will cost you too much.
There are other ways to achieve this using RDP Wrapper but by taking that ...