cnckitchen did a pretty good comparison of different gitd filaments. There's a video on their channel too.
I don't remember if the comparison covered this, but I would expect PETg to work better than PLA for gitd stuff because it's inherently more transparent, right?
I should have 3 different glow filaments somewhere, one PETG, two PLA. Typically I preferred the PLA versions - they had a bit more uniform glow. The PETG one had brighter spots, but as it was mostly transparent individual spots were more visible than with the PLA prints.