Since switching to a dumb phone I've gone down the same path. I already was an avid photographer but I've added a typewriter and a nice pen/notepad which has gotten me writing again. I've also read more books than I've read at any other time in my life, it's really incredible how much time I was wasting.
Which dumb phone? I would like to try similar, but there are always certain Android apps I need (banking apps like BankID, payment apps). Do you get a "pure" dumb phone and then a separate Android device for when it's required, or a dumb phone which does a little bit of Androiding?