I am on a Linux mint 21.1 system with wine (version 7.0.1), vara HF (4.7.2) and winlink (22.214.171.124), working without problem.
Now I've installed VarAC in the same winebottle. It does start (eventough vara gets restarted 3x in the process). I am able to go to the config screen, where I choose cat controll and frequency thru cat for my FT-991 (NOT the A model), and the appropriate com settings for the cat port (com33, 9600,n,8,1). I have selected 'unix compatible mode' at the bottom as well.
In the config screen I need to press the 'test PTT on' button twice (!) to get the tranceiver sending, the 'test PTT off' button twice to stop sending, and I need press 'test' at the frequency selection twice for the tranceiver to change frequency.
Obviously, in the regular operation screen, I can only receive signals, tuning or sending does not trigger the transmitter into transmit, not even when I try to repeat the action.