Of course you wake during the night, not only is this a natural occurrence, but you must be peeing like a horse all through the night? You could try not drinking 2 litres of water an hour before bed and maybe get a bit more restful sleep. Cut it to one litre and keep a bottle of the remaining litre of water by your bed, drink from it whenever you wake up and then the rest in the morning and see how you feel.
7-8 hours of sleep interrupted by a few waking and toilet breaks is still a full night’s sleep so you might be doing yourself a disservice trying to force yourself to sleep longer. Have you tried getting out of bed when you wake up naturally at 6 and starting your day slowly? With a shower, a cup of tea and some reading, or light chores (doing some dishes etc) for example?
If I don’t get up when my body wakes up but try to force it back into a new sleep cycle, I get all kinds of lethargic and foggy and feel tired for hours. I thought it was just a fact of life until now starting to force myself to get up and active as soon as I woke up
Adjusting your schedule might also help with the restlessness during the night but if you finish working out at 8:30 and go to bed at 10 with no issue falling asleep then I don’t think the exercise is the issue. More so the food, but if you have a routine that works for you and you can’t do exercise in the morning then try some other changes first.