I am also an introvert with ADHD! I find the simple hobbies that hold my interest are the ones that have an element of problem-solving because there is a definite start and end, along with plenty of yummy dopamine when you solve it! Solitaire is fun if you are really looking for something simple. Also, I carry a small book of crosswords with me at all times too, those hold my attention longer than physical books.
Audiobooks/podcasts about my current fixation + outside activity (like roller skating, walking, cycling, jogging, etc ...) = the only way I get myself outdoors these days. I use Libby instead of Audible because nothing is more punk rock than the public library.
Speaking of the library, I think they are an untapped resource for people! I am a photographer and I don't have the money to buy my own equipment at the moment, so I check out equipment from my library. You can check out instruments, games, video game consoles, I have even seen Tarot cards (which I might advise against that one, Tarot is too much of a personal process that is energetically sensitive to the individual, so getting public/second-hand cards can be tough)!
The best hobbies for me are the ones I can pick up without feeling too guilty about leaving behind just as quick, the attention is gonna go wherever she wants, I have no say. I try and wait to spend any large sum of money on a hobby I am not married to yet (like buying a bunch of yarn, a sewing machine, climbing gear, etc).