Hes basically on a starvation diet, his is why it's so important for people to build up there metabolism. My maintenance calories are around 3500. Makes cutting a lot easier.Sounds like you made it half way to your goal and you’re already super low calories. At this stage the only true option is increase cardio or go into a reverse diet. If you cut calories from here you’re going to for sure lose muscle, not fat. Next time I’d try to get your bulk up to 2500 and just cut 250 at a time each time progress stalls. I wish there was a supplement to tell you to take but you already have a good setup.
Also try to get that sleep better and consider if you have any hormonal changes from last year.
Ya I fully understand that can be tough. Honestly I'd just see if there is a way you could get that up (ideally eventually doubling so closer to 8k at least).Average 4-5k steps a day as I WFH and have a 6 month old.
I do put on weight easily hence why I've tried to always limit my calories to nothing beyond 2-2.5k. I eat clean but it seems to be more fat than muscle unfortunately.