There isn’t a singular exercise. Maybe you just need to find the sport that suits you.
Personally I find going to the gym (which I assume to be the exercise you meant) rather unrewarding. I prefer to have some competition. Now I’m addicted to rowing.
I find the streams on sportsurge to either be low quality or prone to connection problems. Someone recommended 1stream . eu to me and I haven’t had buffering issues yet.
Not to disturb the circus, but with some discipline and mental rewiring it’s not at all impossible to get your dopamine from healthy foods. Exercise is also an excellent source. Fast food might give you effortless happiness quickly, but a healthy lifestyle will be much more beneficial to your well-being in the long run.
Mastodon is definitely a harder sell than Lemmy due to the nature kf following people rather than subjects.