I have just started experimenting with Linux Mint - an environment I’m not familiar with at all. However I succeeded in installing and running the Trial for Linux 64bit Installer Version 3.29.6 on an Asus Zenbook laptop.
The screen-scalings were all awry and it took me some time to make the user interface resemble what I am used to but what struck me particularly was that text was pixelated and indistinct - especially dimensions. Neither could I get QCAD to fire up instantly every time as it does in Windows.
By way of comparison, I then loaded the Windows version (3.29.6.0) and ran it through Wine. It looked perfect! Without any adjustments at all, everything came up as it does on my Windows 11 machine. Scaling was all exactly right and text was reassuringly sharp and crisp. All dimensions were clearly legible. But alas my joy was short-lived. The WINE translation proved flakey and unstable and crashed several times in a matter of minutes so I hastily abandoned it.
I wonder if my issues with Linux are simply due to my ignorance of the OS, or must the Linux user (as so often seems to be the case) spend much time and effort tweaking things to get an acceptable result?!
Linux operating systems are highly versatile as users can choose between all kinds of different drivers, window managers (X11, Wayland), desktop environments (Gnome, KDE, …) and various preferences which makes it almost impossible to tell what might be wrong in your particular case.
I’d first try to install a different package:
→ All Downloads
→ Linux 64bit Qt 5.14 (Wayland support) Installer
This might work better on your system.