Regarding hobbies: Maybe you could start playing videogames with friends? I know that compared to what @robbert.f suggested it’s probably not the best or healthiest hobby, but the easiest to get into since you only have to turn on your PC.
I’d suggest you “Ori and the blind Forest” and it’s successor “Ori and the Will of the Wisps” which are both unbelievably beautiful (although somethimes kind of hard) jump’n’run games. The music and the artwork are breathtaking.
For multiplayer I’d recommend Factorio which is about automation and building a robot factory on an alien planet. It’s great with two people and at least I was able to really sink into it and forget about the rest of the world for five hours in a row.
The games are 20€, 30€ and 25€ on Steam, you can however get them much cheaper on external sites like allkeyshop.com. All three of them work fine on Ubuntu-based Linux.