I really do not know how you made it working in the old setup. Somehow the RDP session stays openned even after disconnecting from it. I never seen this.
In your case I would concentrate to set-up true unattended robot e.g. based on this post - old but still valid until version 2021.4
Key points are:
- make entry in Credential Manager “UiPath:user=<domain\username>”
- scheduled task is running under <domain\username> with settgin “Run whether user is logged on or not”
- UiPath.Service.Host.exe installed and running
- UiPath.Service.UserHost.exe NOT running under <domain\username> account
Cheers