Ender 3 Z offset ignored!

hi, a week or so ago i installed a BIGTREETECH SKR 1.4 Turbo with TMC2209s into my CREALITY ENDER 3 with marlin 2.0 BUGFIX and a BLTouch, got it all working and it was printing lovely. then i ruined it for myself by trying to lower the z offset to get a bit more squidge on my first layers. from there it all went very wrong.
i dont know what happened or what i did wrong but now it just ignores the Z probe offset altogether, when it was working the offset was set as -1.19 but now i can increase or decrease it and when i go to print the nozzle is miles off the bed (close to 1mm id say) but on the LCD it just says 0.2.
ive tried going back through the offset wizard, and it sets the offset ok, then i go to print and its too high.
tried setting it with commands via pronterface, same thing.
i really dont know what to do now im starting to lose my sanity over this so if anyone has any advice i would greatly appreciate it :)