That the mindset… but that’s also metabolically stupid. That said, I fell for it as well so no judgement. I wound up with RMR of 1700 as a (at the time) around 250lb pretty active dude with a physical job that worked out 6 days a week! I stopped losing because I was eating what almost every macro calc said which was between 2500-3000 (where it should have been). I’ve got it back up over 3000 now so I get to eat adult sized meals again, but it’s not a place you want to go, I can assure you.
There’s absolutely times to listen to what your body’s telling you, then there’s a time to ignore it because you know better. Many of us can’t trust our hunger or satiety signals, keto isn’t the magic signal fixing pill that many think it is, for SOME it is, for many others it’s not. Under 1000 calories is starvation, I don’t care how big or small you are.
I’d personally stay away from OMAD, but if you can eat a days worth of food doing it, I guess it’s fine. I honestly don’t see an advantage to it at all including fixing blood sugar problems, that can be done just as well by correct diet. But I’m also for people doing what works for them… as long as it works and isn’t causing negatives. To me, a lowered RMR (after dealing with it myself) is very much a HUGE negative.