I've generally found quite a lot of success at abandoning goals / "destinations" for most things, and focusing on the "journey": don't aim to "be fit" or reach a specific weight. aim to "do one more thing" to make progress along a direction. every step in that direction is success, every bit is something you weren't doing before and is something to be happy about. it doesn't have to be big at all - have you done one…
There are may other activities that will get you fit and are what I think are way less boring. Sometimes, it is a literal journey, as in hiking. But also team sports, combat sports, climbing, actual gymnastics, etc... Here, you actually concentrate on the activity itself rather than on the end goal.