Please Help With Old OSS Sound Application

I'm having super hard time trying to make an ancient programm (TeamSpeak2) to work under ubuntu 20.04 (tried with several versions of ubuntu same result). After weeks of googleing, I maybe found the problem. The program starts but I can't hear no sound whatsoever. I've tried to commence ossinfo and this is the result

Version info:   (0x00000000)
Platform: Linux/x86_64 5.4.0-29-generic #33-Ubuntu SMP Wed Apr 29 14:32:27 UTC 2020 (dex)

Number of audio devices:        0
Number of audio engines:        0
Number of MIDI devices:         0
Number of mixer devices:        0


Device objects

MIDI devices (/dev/midi*)

Mixer devices

Audio devices

Nodes

it looks like the oss driver can't find any sound card while I have got two. I can't disable pulseaudio even if btw I've tried with no effect at all. I know ubuntu has deprecated support to all OSS world (can't get why btw...), but I know several pepole under ubuntu can run old OSS sound application with no issue. So maybe there's a way to fixit. I've got all the alsa and osspd packages on.

Do you know how can I make the OSS driver to see my cards please?

thanks a lot for your help...