I ran into some difficulties when upgrading from Ubuntu 22.04 to 22.04 - will not bore you with the details.
I had to install a new graphics card to work with 24.04 to get a suitable NVIDIA driver - now GT 1050.
I had to re-install all software and now have a working system with the exception of QCAD. I have recently renewed my license to QCAD Pro and have had another attempt to install this morning. I have followed the installation procedure and all seems well but the QCAD icon does not appear to work.
I have tried running from the installation directory directly using ./qcad but have had no joy.
The PC is dual boot and the windows 10 installation of QCAD works well.
QCAD version 3.31.2
11:20:10: Info: Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.
Warning: Application already running. Aborting…