How is your spool?
I had some failed prints like that and found that the spool was catching on something on the back of the p1p.
Start out by disclosing your brand of PETG. Personally, I’d bet the speed and max flow is too high to consistently extrude. Some brands you can run at 10-14mm3 on the max flow rate, others need to be slowed down to 5-8mm3.
IMO, PETG really isn’t that easy to print.
A quick way to test this theory, is mid print… if the print start to look like this change it to “silent” speed and see if it magically starts printing great. If so, you’ve got too much max flow volume.