You're aware Ubuntu MATE 20.04 LTS isn't supported any longer.. ie. maybe re-read Ubuntu MATE 20.04 LTS reaches end of life . Ubuntu Desktop/Server/Cloud/base get 5 years of standard support; flavors like Ubuntu-MATE come with 3 years.
Ubuntu LTS releases have two kernel stack choices; the GA kernel being the older release; and the HWE being the GA kernel stack from the later LTS release (ie. 20.04 had 5.4 kernel if you're using the GA stack & 5.15 or the GA stack from 22.04 if using HWE). If you're using the older GA stack on your 20.04 install (it was installed using early media) you could try switching to the newer kernel stack (meaning newer kernel modules, aka drivers)