

Grid infill is crossing, get a decent blob or buildup and you could have nozzle collision, I personally like gyroid but it is slower.
Had a similar failure on the mk3s, what does the belt tension test return? Stealth mode may help or be the cause, anecdotally I’ve seen mention of motor temps, the old rambo board running stock firmware they got toasty when printing in the enclosure in the summer, stealth helped me limp it along until I did a board swap and changed to klipper. I don’t know if this is an issue with the mk4 as that’s not using the older Rambo based boards, but something to consider as well, had it happen even after I did the first abs rebuild.
Edit: too tight can also cause issues, not necessarily skipping but having it trigger the virtual endstop, prusa has an article for troubleshooting layer shifting. Also probably with checking both axis to ensure they’re smooth and consistent across travel, seen an over tight x carriage back cause too much resistance and have false triggers.
Says a lot that it can run pretty much maintenance free for a year and a half! I only had issues with my mk3s doing daily enclosed abs prints in the summer, the original petg softened and it ended up killing the idler end of the x axis (idler mount deformed suddenly under tension after like… 1-2 months of that). They may not be the fastest or fanciest but they’re easy to service and in my experience pretty reliable, I repacked the linear bearings after a year or so out of precaution when I did a full rebuild, but I don’t expect needing to do that for a long time.
Here’s another prusa article for infill patterns, the prusa knowledge base is really decent and applicable to a variety of printers, I use my voron a lot but still refer to it.