Yeh, but I was on Mint 17.3 (shows how long ago I set up my machine which has only ever run master back when 2.8 was master). Back then you had to compile the kernel to get PREMPT_RT.
Eventually, Master dependencies could not be satisfied so it forced my hand. I played with MXlinux but it would not support my networking hardware reliably. So then I went back to Mint 19.3 because V20 had not worked before. The Python version rolled forward to 3.7 and Mint 19.3 was only on 3.6 so my config broke when Pulled an update. I could not get the python versions working together (right when the python3 transition happened). So then I decided to give Bullseye a try as it did not include Python 2.7. I set it up on another machine initially, then spent a lot of time setting the environment up on my production machine so I could mange it remotely and I decided to build and install the debs. I had never ever done that before! That was a mistake! Seems like when you do that, you can never run RIP again!
In all honesty, the change to Python 3 and the need to run master branch to get QTplasmac has created a minefield in my view. Everything is very unstable. I tried to revert to my gmoccappy config. Gmocappy runs on Python 3 these days, but plasmac insisted it needed to be upgraded to qtplasmac. I don't understand why.
Bullseye is a good option if you want to totally remove Python 2.7 and don't mind compiling Linuxcnc. But Debian requires a lot of little things to be done that other distros don't eg Auto logon, sudoers group and manual network setup