Went with a DEXA scan for this. Female here.
Wrapped up a cut back in January at 10% body fat, 136 pounds.
Over the following six months bumped calories up by roughly 800 and cut cardio from around 3 hours down to 1.5-2. Just got another DEXA done and it's showing 14% body fat, weighing slightly less at 133, but the drop looks like it came purely from muscle. Genuinely can't figure out how that happened.