PETG has a tendency to string when it oozes out the nozzle while it's travelling (moving without extruding). Sometimes that builds up on the nozzle (it also like to stick to the nozzle) and eventually you get a blob deposited into a wall somewhere. This printer with its default settings was fantastic (at first) for PETG as it didn't string at all. This stuff has carbon fibre mixed in so it's different (and needs a hardened nozzle as it is abrasive) but I'm trying to get back to that perfect PETG print. You find a filament that works perfectly and suddenly it's not available and you're back to square one.
Support seems to break off PLA much easier as it's brittle. I suspect that PETG also spreads a bit more so the support is much more joined to it.
PETG was my go-to because I could run my last printer without the layer fan and just make do with the waft of the hotend fan. That was key as it was close to me whilst I was at work and Creality had done weird things with PWM that meant it was noisy and sort of crunchy - even with a Noctua.
A deburring tool is quite good for getting rid of brims if you are having trouble getting those off cleanly - again, more a PETG thing than PLA.
My fans are almost silent on my Ender hotend. What are you doing exactly? I decoupled my fan from the hotend and run it from the PSU directly with a voltage adjuster to get it where I want it.
I also put all my electronics, psu and screen in an external housing (making sure to run a ground wire to the frame btw), and use a large 120mm fan to keep everything cool in there, with the original fan hooked up to a temp sensor for backup.
CF you need a hardened nozzle, ideally 0.6mm to avoid clogs.
Do you dry your filament prior to use? I run a food dehydrator on my filament before printing.