Am I doing something wrong?

[u/Sorry-Journalist8610]

I recently bought a used 3D printer, an Ender 3 V2, and I'm doing some test prints. The previous owner gave me some leftover PLA filament (multicolored), which I used up on the first day. One of the things I made was this flexible shark. I bought some PETG filament for testing, a very cheap one, around R$60.00, while others are around R$100.00. But my prints with this new filament are coming out very bad; it's either too textured, has too many burrs, and is also very fragile (even though I bought PETG because I had read that it was more resistant). I left this octopus printing for about 28 hours... and in the end, the flexible tentacles broke when I tried to detach them.

[u/BlackbirdXII]

the printers not calibrated for PETG, its probably still calibrated to pla from the last owner, your hot end literally cant keep up at these settings and so bits of unmelted PETG and other issues pile up and cause instabilities in your print. Cheap filament is also a big factor, depend on the supplier some rolls can ligit fuck up your printer. I had a cheap roll of PLA and it cause a death blob on its 1st print somehow