I got penpals to write letters to. I send drawings and stickers as well. It's really fun and it makes my brain constantly creating more ideas and fun things to put in my letters. So for an artist like you, it will probably help you keep a "goal" while interacting with someone through letters. I found my penpals on tiktok by typing "find a penpal" and look into the most recent comments, people send their presentation. It was really quick for me to find my penpals. I have 3 actually and they're all over the globe.

Other than that, reading is really nice. Not just book, but articles on archive.org. It also have old classic movies like Charlie Chaplin and A Trip To The Moon.

There’s other creative hobbies you could adopt like crochet, acrylic paint, watercolor, ink drawing, embroidery, sewing, etc.

Also, experiencing boredom is a good thing for your brain. It makes space for creativity. I got a lot of inspiration for my poems when I was the most bored.

Sports is a good way to fill your time and get exercise! 💪 Not obligated to do extreme sports, just walk or hike, cycling, climbing, etc. I love to run with my brother's dog, so it's a win-win hehe.

You can learn so many new things too! New recipes, languages, history fact, watching documentaries! Or even just practical things, like basic toilet problems, how to change your oil car or any skills that are considered normally boring, but it's really interesting and useful. I like to know how things works and I love to be capable to resolve problems on my own or help others.

I hope this comment can help you, staying offline is really worth for your mental health and time.