There was never a manual for TotalMix FX itself. As some TotalMix FX features depend on the Hardware (capabilities of the recording interface) it is part of the manual of the recording interface.
But there is an online help, see
TM FX: Help -> TotalMix FX Help
If you installed Beta versions of 2.x from the forum, then you got in most, if not all, cases only the updated binary, but not the online help.
TotalMix FX 2.x now comes with an installer; if you install it that way, the online help should be installed and accessible.
https://www.dropbox.com/scl/fi/cbe080q5 … b&dl=1

Whether TM FX 2.x will be updated in driver packages in the future, I don't know.
Please note: I am not sure, but it is rather likely that after installing / updating a driver with an older version of TotalMix packaged, it might install the older version of TotalMix FX.
So it could be the case, that you might need to repeat the installation of the latest TotalMix FX 2.0.
This, until over time, all driver packages change and "support the new situation".
BR Ramses - HDSPe MADI FX, M-1620 Pro D, 12Mic, UFX III, ADI-2 Pro FS R BE, Nuendo 15, Win10 IoT Ent