30mm isn't that slow for pet.
It's weird, sticky stuff when melted.

One reason we usually go for pet-g - and yes they are quite different. The 'g' stands for a glycol molecule that's tagged on to the polyethylene terepthalate.
Changes the material properties quite a bit.

okay you've got a direct drive extruder - so keep your retractions down to under 2mm and run it slow - say 30mm/s.
Also cut your fan speed right down.
See what happens if we treat it like flexible filament.
Which If I remember the roll I accidentally bought - it's pretty bendy stuff.

Is it sticking to the bed okay ?