I just can say how I do things (but I never gained much muscles or lost fat since ages I just enjoy my eating and fasting alike)…
I can’t and am not willing to force things (without some very serious health issue reason but I don’t have that). I typically fast only if I am perfectly satiated and it’s the easiest to do. Sometimes I push a little but still eat when hungry except if I get that strange cute hunger I like and what never triggers eating. I get determined to fast - and my body decides if it cooperates with me. Determination is key for me, once I fasted for 120 hours out of curiosity and determination without problems (I felt odd in the end but that was probably due to me not consuming any sodium during the whole time. it was funny). But if my body tells me it WANTS food, I eat.
OMAD is something I really want to do longer term sometimes, it didn’t happen yet but I have OMAD times. Starting is the hardest but with some planning and a tiny bit of self control(?) I manage to eat an OMAD sized satiating meal at the right time for me. And a big meal lasts for a day for me but I am ready to eat much enough again so it’s fine for a few days. But my energy need is way smaller than yours, IDK about our eating abilities though. Choosing our food is very important, at least to me but probably for most of us. Not anyone can eat a big meal using just any food on keto, to put it lightly.
I personally need to be well-fasted when I do my workouts as I only have enough energy and mood for it at that time. Not too late, 23 hour after my last meal is problematic but 18-20 is fine for me. But many people like/need eating before workouts. I need a substantial meal afterwards (not immediately but soon), at least I did and I always do it so I can’t check if it changed lately. But probably not. And I feel it right to eat after, my body probably really need the nutrients then.
It probably doesn’t help people. They usually are “strong” and just don’t eat when they decide. It’s very foreign to me. I can’t even wait until hunger most of the time… That’s one reason I want OMAD, a big, good meal gives me perfect satiation for almost a day and I just don’t want to eat in that blissful state.
OMAD or a longer fast is easier…? Can’t tell, it depends on many things. If you want autophagy too (as I do), try a longer fast. But maybe you should just wait until a really serious hunger you can’t ignore and if it gives you OMAD, good, if a longer fast, even better. But as I wrote, me and eating according to plan isn’t a thing, I just make a plan and let my body decide what it allows. Making the plan already does its job to my mind so it’s up to the physical part.