I always run with this line in the Machine End G-code commented out:
; pull back filament to AMS
M620 S255
I change it to:
; Do not pull back filament to AMS
; M620 S255
The result is similar to a cancelled print in that the filament is neither cut nor retracted (the toolhead still moves close to the cutter - I could probably comment out some more to avoid that but I never bothered).
When starting next print, the printer knows from the AMS sensors that filament is already loaded, and which. Even if it was powered off in between. So it always does the right thing: If the new print uses that same filament, it just uses it and saved me some time. If not, it starts off with a filament switch.
IMHO Bambu should remove that silly unload in the end G-code. Or make it optional - but I really can’t see why it would ever be needed.
Edit: There is one situation where my hack has a drawback: If, after everything cooled down, I want to replace the spool that is still loaded, I need to unload it first. And that means I need to wait for nozzle to heat up. Maybe I could manually press the cutter lever, then retract from touch screen with nozzle stone cold. I haven’t tried that but I guess it will work.