I guess this may indeed be a z issue, those diagonal lines could be when the nozzle moved from corner to corner without laying material down.
I don’t think this has anything to do with the material or temperature or anything like that.
I’m not overly familiar with the Ender, but maybe run a bed levelling protocol or other calibration option? The plate is probably toast unfortunately.
baduhai@sopuli.xyz 3 days ago
I also destroyed my Ender 3 V3 SE’s stock plate with petg. It just sticks too well to petg, I was only able to reliably print petg when I changed plates.
user_6282638282@sopuli.xyz 3 days ago
What did you replace it with?
baduhai@sopuli.xyz 3 days ago
I replaced it with a cheap textured pei coated metal plate. It doesn’t stick to pla as well, but it printed pretty much everything I threw at it.