I used to bike to the library after work, about 4 km each way. It started out as a form of exercise (the library happened to be along the bike path), but eventually I was going almost every night just so I could pick a magazine from the library's large selection and read for 30 minutes or an hour. I still had my phone, but because I set out to go to the library, and the form of transport was so focused and meditative, when I got there I was able to just read without being distracted, something which was very difficult at home.
I don't know if you have ADHD, but I do. (Maybe you have it and it's undiagnosed.)
I've found that rather than worrying about my own motivation or lack thereof, it's better to focus on sleep, exercise and diet. Get those things and "motivation" will come. If I'm not motivated, I try to improve those factors.
I guess I'm saying that because it sounds like exercise is important to you as well.
