Ubuntu MATE 20.04 LTS is End of Life
Ubuntu 20.04 LTS reached End of Standard Support long ago now too, meaning Ubuntu support is EOL, and the release is now supported only by Canonical via ESM.
This isn't a Canonical Support site; they provide their own support venues that are not used by the Ubuntu project.
FYI: Both GA & HWE stacks from 20.04 cannot run PipeWire as the kernels are too old. PipeWire requires kernels provided by Ubuntu 22.10 and later, or if using 22.04 you cannot use the GA kernel stack either with PipeWire; your Ubuntu 20.04 LTS HWE stack was backported from 20.04 thus is PulseAudio only.