There are a few things I do on my computer that don't require the internet. I write, I do archviz, and 3D printing, for which, I can make my own models in Blender. I could pick up photography again. I have games I play that don't need internet access to run.

I also sew, as a hobby, which I could do on my hand-cranked Singer sewing machine, which doesn't even need electricity. I also have a few home improvement projects I've been dragging my feet on.

I'd miss it, but I'd be fine.