I suspect that all these aggressively advertising gyms, once they get hold of your membership they won’t let it go that easily. There is speculative hope that they would break even later, once pandemic subsided. Suppliers of exercising equipment make much more money nowadays than empty public sports facilities.
I avoid gyms completely, create my own workouts at home. In this weather you can go to parkour areas, jogging, cycling, walking, running and other outdoor activities with ball on fresh air e.g. I do regular sessions of tennis on the wall. Walking junior in pram is one of them.