make sure everything is as square as you can make it, tension and eccentric wheel not too much or too little, no broken parts, get some filament you dont care about and dry it then go through this:
skip any voron or klipper specific stuff and follow the marlin instructions for each section that has them.
Its a huge pain in the ass to do the whole thing, but you will be able to rule out everything that can be ruled out. Some of the sections are more or less once per printer, some per toolhead change, some are once per filament type, some are per individual roll.
make sure everything is as square as you can make it, tension and eccentric wheel not too much or too little, no broken parts, get some filament you dont care about and dry it then go through this:
https://ellis3dp.com/Print-Tuning-Guide/
skip any voron or klipper specific stuff and follow the marlin instructions for each section that has them.
Its a huge pain in the ass to do the whole thing, but you will be able to rule out everything that can be ruled out. Some of the sections are more or less once per printer, some per toolhead change, some are once per filament type, some are per individual roll.