Ton of questions here needed for someone to give you the best advice. How long have you been fasting? How much do you eat and macro breakdown? And there’s multiple facets to your post.. are you looking for an answer on sleep (would need above info)..
As far as the training, if you are trying to build muscle it’d be best to at least vary your workouts by at least trying to lift weights 1-2 days a week. Doesn’t have to be long. Focus on compound movements 3-4 sets around 8-10 repetitions, try to pick a weight that is difficult but that you can complete the workout.. but that it becomes very difficult the last set. Track how much you lift each time, try and go slightly up in weight each workout or do more repetitions. This is called progressive overload and is a staple of muscle building.
As far as when to eat.. most optimally you’d want to break your fast within 90 mins around your workout (before or after) to feed that muscle repair and growth. You’re trying to intentionally spike your insulin for an anabolic response.
That’s what I do currently, workout in the morning and break fast later in the day. I’m still mostly focused on weight loss so it’s slight gains and maintaining of muscle tissue. Though I’ve certainly put on some mass.
My understanding is that as long as you’re working out properly and getting daily protein goals that’s most of what matters. I leave grinding out those last percentages of efficiency of perfectly timing out workout, meals, protein doses, and such to folks training at a much higher level.