What can a person replace tv shows, movies, and other zombie-brain entertainment with? How can attention span be improved?

As part of my endless and possibly futile quest to be a less pathetic version of myself, I've embarked on a campaign to stop watching TV and movies. For me it's low hanging fruit - some people really love movies, but I honestly can't remember the last time I watched something that I truly enjoyed. It's just something to fill dead time when I'm too tired to think. It BOTHERS me that I've spent so many hours mindlessly watching shows that I didn't even like. I feel like I'm wasting my life every time I watch TV.

I've tried reading and podcasts with limited success. They're good to a point, but the type of content I like is usually either pretty heavy or requires some thought (philosophy, human rights, law, etc. are my areas of interest), and I'm increasingly having trouble with my attention span too.

I already cancelled Netflix a long time ago, but I just never found a good replacement for it. Usually I find myself doomscrolling or watching the same few movies I already own or playing chess on my phone. I decided when I started that I'd let myself finish watching the shows I already followed, but just wouldn't expose myself to any new ones. Now one of the last two shows that I had been following has been cancelled (which is understandable, the last season was AWFUL) and the other won't have a new season for a while because of the strike (go strikers), so I'd really like to make TV and movies a non-factor in my life.

So I'm looking for advice here. What other activities are less of a waste of valuable time but not mentally tasking? Has anyone had success improving their attention span? I'd love to become a bookworm but goddamn is it ever hard to keep my ass on a chair long enough to get through more than two chapters. I don't even know why my attention span is so bad - I actually used to tear through book and had no issue concentrating until about 5-10 years ago.

Any ideas?