There are many scientific ductility and strength tests comparing the 2, PETG often gets compared with ABS too for strength. PETG is in every way superior when it comes to outdoor, or warm environments. PLA has a glass temp lower than PETG and the sun alone can glass even the white and translucent materials. I expect PETG to survive outdoors. Where PLA is quite famous for failing outdoors. What are you printing on? Which PETG and temps vs flowrate adjusted for the material vs your printer? Ive had great success with matterhackers PETG and Bambu PETG, as well as some other generic chinese brands. At least with a Bambu. It took tuning flow rates and heat for the material on a few test prints with the old ender 3.