Ok here is the issue.
Before I flashed the new OS version I had zdoom setup with many Wads and PK3’s and everything worked like a charm with sound. But after flashing the new OS there is no sound at all after reinstalling zdoom.
I have installed openal (libopenal1), fluidsynth, Timidity etc…
With Timidity I get music but no sfx (gunshot, menu sound…)
You need the dependencies before compiling.
sudo apt-get install g++ make cmake libsdl2-dev git zlib1g-dev libbz2-dev
libjpeg-dev libfluidsynth-dev libgme-dev libopenal-dev libmpg123-dev
libsndfile1-dev libwildmidi-dev libgtk-3-dev timidity nasm tar chrpath
On OS V0.4 I was able to compile once but never got sound to work.
So I did a Sudo apt-get update, reinstalled the dependencies and tried to recompile without success. 10 times, without success. So I gave up. This, to me, sound like there is an issue with the new OS.
On OS V0.3, everything compile right away without issues. So I went back to OS V0.3. This new OS update is a mess unless you are a Linux freak or a black belt in compiling.
0.4 has midi support from what I remember reading, so once you have a soundfont set up, you should be able to use that. OpenAL should still be working though, unless it has been updated. Being a system dependency, try a sudo apt-get upgrade on Debian, or even try Debian 10 Buster. But also that could break things depending on what dependencies exist.