If you are stringing with PETG, then I would suggest turning down or off the cooling fan in the nozzle and running the filament at the top recommended temp you can, it needs those high temps to properly melt and mesh with the other layer lines. Also, slow the print down if you can, but turn up the travel if possible so it has less time to sting up while moving from one side to the other. Also you might mess with the flow rate, if it's too high, it can cause stringing with PETG.

Not sure what printer you are running. This is what I had to do with my Ender 3's. I haven't had any issues (or VERY FEW) issues with stringing with my BambuLab A1 and A1 Mini. But aside from a different printer, figuring out the PETG stinging thing is one for the ages, lol.