When using Illustrator 2020 or 2021 with a graphic tablet, that means you have to use at least macOS 10.14. That system has some strict security and privacy settings (that have become even more restrictive in later versions), which also restrict the use of graphic tablets. So what you need to make sure is:
Get a compatible driver for your tablet and the system you are using. If you cannot identify your tablet on the producers' websites (which is likely, given the cryptic names, production numbers and makes), then ask their support staff for help.
Set up the tablet in the macOS system preferences. You need to allow it to drive your computer. The tablet producers have instructions on how to do that. You need to set them up according to these instructions. Leave out a step and it won't work.
If you are using a non-Wacom tablet and it still doesn't work, then install and set up a Wacom driver on top of that. This is a hack, which has so far worked for most users.