Five weeks of identical scale numbers but two inches off your waist and better glucose/A1c is not a plateau in fat loss — that’s a measurement problem, not a progress problem. The scale is a dumb sum of fat, muscle, glycogen, food volume, and water, and lifting 3x/week can absolutely add intramuscular water and glycogen fast enough to hide 2-3 lbs of fat loss.
I’d stop judging by weekly numbers and switch to a 10-day rolling average plus waist at the same spot: navel, relaxed exhale, morning, before food. Did anything change around week 12 — creatine, new rep scheme, more carbs, worse sleep, extra sodium? Any of those can add a few pounds of water while your waist shrinks.
If your lifts are still progressing and waist is down, I’d hold calories another 3-4 weeks before changing anything. The one thing I’d check is whether your weight trend is truly flat on the rolling average or just bouncing inside a 2-lb range.