Just had lots of problems connecting to USB and serial devices due to the brltty.services. This is what finally worked for me (Ubuntu Mate 22.04 on RPi4).
sudo systemctl stop brltty-udev.service
sudo systemctl mask brltty-udev.service
sudo systemctl stop brltty.service
sudo systemctl disable brltty.service
sudo reboot
you can check these service are inactive/dead by doing
sudo systemctl status brltty-udev.service
sudo systemctl status brltty.service
After doing the above I was able to recognise my arduino based devices and other usb devices.
I also found that you need to install linux-modules-extra-raspi to recognise any arduino uno based devices.
So the final verdict? Will an update to v1.9.6 stable work with 22.04 or do I have to go to the nightly? I'm particularly concerned with the pl2303 converter. I have to run an older version for it to communicate with my EQ6R. Anyone running latest (stable or nightly) with an EQ6R on 22.04?
Calculating upgrade... Done
The following packages were automatically installed and are no longer required:
indi-beefocus indi-weewx-json
Use 'sudo apt autoremove' to remove them.
The following packages have been kept back:
indi-full
0 to upgrade, 0 to newly install, 0 to remove and 1 not to upgrade.