Whatever server you run, the performance is related to what your physical hardware is capable of and what the guest OS is capable of. If you use most of the defaults with VirtIO you will get near-native performance on any modern machine.
As far as Windows (Terminal) Server and the rest, it works, check your licensing though, Windows clients are typically not licensed to be ran with more than 2 simultaneous remote users, which is 1 administrative RDP and 1 client RDP. If you want to use something like what others mention here, especially in commercial setting, you must obtain a Server license + CAL from Microsoft, even if you’re not using ‘their’ software.
TSPlus etc is just an extension/replacement to RDS on Windows, it does not provide additional per-seat licenses for multiple users, just like using SQL Server, you must have a CAL per client/user even if you use the Linux version in Docker on Windows or use a web frontend, or if you’re running Windows in VM, you must have a license for each VM instance. TSPlus does hack the registry in a way that Microsoft can detect, so if you are going that route and do not pay for the appropriate license, expect to fail your SAM audit.
If you want a multi-user terminal server for free/cheap, use Linux + XRDP.