Let's check off the boxes.
So far, you have
- Installed a full version of LM 21.2
- Learned how to take a Timeshift snapshot to restore from if needed
- learned how to enable and run your software firewall
- Upgraded to LM 21.3
- Run updates on that
- Made the acquaintance of inxi for looking at your system configuration, and supplying it to others if need be
- Installed a package from Terminal (even if Timeshift was not actually needed, lol)
... doing very well, and I don't patronise.
You can brainstorm for yourself, make a list and run it by us.
You could have a read of 10 things to do after installing LM 21.3 Cinnamon (actually way more than 10, lol)
https://easylinuxtipsproject.blogspot.com/p/first-mint-cinnamon.html
You want to look at CAD options?
There is a site call AlternativeTo - make it your friend. Just type in your search engine eg
"alternative to autocad"
and you should find it
It's always a good idea to look at what may already be in your Repositories for installing, and for that we can talk about
Synaptic Package Manager
which you already have installed.
Let us know your "druthers" (I'd rather do this, I'd rather do that - are what I call druthers)
Cheers
Wiz, and give yourself a pat on the back.