Stall when stopping

[RoadBlock]

Hi all, new member but owned my 99 x1 for a long time. It’s more recently started a weird issue where it either stalls or sputters when stopping with a stronger force. Generally if I am not going too fast and let the engine slow it down things are fine. Where it acts up if I have to use brakes to slow down faster than that. It doesn’t seem to be a fuel supply issue as I can pull really hard on acceleration all the time, no issues there. Cornering also seems to be just fine as long as I am accelerating or mostly holding the same speed. If I slow in the middle, it sputters.

Two main scenarios:
Clutch out- hold higher or downshift into higher rpm. Jamb on the brakes for a second or two to drop 15-20 mph. Engine will sputter and back fire and mostly stay running because of the engine breaking.
Clutch in- at some speed, jamb on brakes to drop 15-20 mph for a second or two. Engine will idle fine until about a second after releasing and it will just stall if I don’t throttle it or let the clutch out.

Things I’ve checked/done:
- Fuel tank full and fresh gas
- Pump is working well
- changed plugs from champion RA8HC/ HD 6R12 to NGK DCPR8E (yes, plugs were different, not me �&#56900
- TPS reset with Bluetooth and EcmSpy
- no DTC reporting
- wires all look in good condition

I need help. What else should I check?