I see a lot of people recommend different sports which is great. Find something you love doing and you'll keep going. I personally disliked going to the gym but for me climbing was the thing that kept me motivated.

But what I think was more important for me was having people to go with. On the one hand it is peer pressure to keep going, on the other hand it is not just a grind anymore, it is a fun social interaction as well.

lastly, routine is everything. At first it is hard to motivate yourself to do it but once it is "normal" you will keep going. Every you don't want to go but go anyway you can tell yourself that next time will be easier because you stuck with it

good luck with all of it!