(superseeded) Linuxcnc on Linux Mint 19.3 quick and easy installation

KUKA robots above KRC4 should also be run on Linux, not sure abut Mazak and some others. Okuma uses windoze still and a lot of other manufacturers, that really should be the deal breaker for that type of machines.
I had a Kuka KRC1 lock twice in a single run of about two hours, KRC2 once every now and then, and they used a stripped down version of Win. Some days ago i had a big industrial 400A plasma cnc at 8X2.5M try to kill me twice as it would start to violently move the gantry in one direction (my direction) twice when winXP locked solid. Not a nice feeling.
Car industry has long gone to Linux or Android for diagnostics systems. I think only Mercedes uses windoze as their software is developed by Siemens and they have very cheap windoze due to the volume they use, same thing with Bosch, they also use everything from Siemens on the software and electronics side.

What does
uname - a
say ?

in a terminal from the menu or left side on the bottom panel, black square.

Did you install the kernel ?

Reboot and hold down ctrl+shift keys until you get the grub menu.
select the line with RT in the name