I’m using Win10 Pro with RDP Wrapper. Created 3 users and set a terminal name for each of them in Samba.
I don’t think it is an RDP issue - I used a Lenovo win10 tablet which runs samba locally and terminal names kept changing as well.
As for Android mobile client or QMX - sorry but I had a hard time to find any advantage over my setup. It was easy to setup, it’s super fast, I have never had a lag or a database disconnection and I can use the full Samba funcionality including ticket settlement and printing to a mobile printer.