My calculated base metabolic rate, given my weight and body fat is 1750. Add in the thermic effect of the food I eat in a day, that comes to about 1900. Add in basic sedentary activity, that comes out to 2200. Then you add 50 calories for calisthenics, and another 50 for a treadmill session, and that's about 2300. So to lose fat, I have to eat quite a bit less than that. 1800 cal/day would be about a 500 calorie deficit.
What's really strange is that I shoudn't even be able to maintain my current weight, according to Cronometer's accounting, yet the weight on the scale hasn't really budged downward (it's still 177, the only thing that has changed is body fat). So something is broken with their formula. My guess is that their "sedentary" multiplier might not be accounting for non-exercise related activity correctly (pacing, standing up, fidgeting), which people naturally tend to increase or decrease depending on calories.
Three years ago I lost some weight early in the pandemic, and I had the same kinds of problems actually losing weight. I found in the end the only thing that worked was alternating one day with a 250 calorie deficit with another day with a 750 calorie defict. It was hard to get used to but it worked. I was very hungry some days, I must have had alot of willpower, but the weight of the scales dropped consistently. The only exercise I did back then was walking alot, I got a pedometer and tried to do 10,00 steps a day (I ended up wearing out a pair of sandals, in fact, from all the walking). The diet left me lean at 160, though. But I have gained it all back since then, because I had to basically keep eating in a strict way to keep the weight off (summer rolled around and I couldn't keep walking like that consistently).