- Do not eat or drink anything but water at least 3 hours before when you are going to bed.
- Do not have screens in the bedroom.
- No screens 1 hour before before bed.
(That last one I utterly fail at, but I am mainly doing textual things not from an attention-economy leach on the screen so, and it works out. Either the other 3 is enough or that screen time is sufficiently less stimulating.)
I've figured lately that working "hard" at chores at home can replace some of it, the point is to not be too lazy.
Good quality sports cloth are not that expensive anymore and make winter outside exercising possible and pleasant. Really, buy merino shirt and sport pants.
The other option is fast wall outside, but that have to be longer to amount to exercise.
Third option is to have a look at bodyweight exercising. Most of it you can do at home with zero equipment and don't require much space. Some of it requires stomping, so you may have to skip those is someone lives under you.