At my wits end with extrusion problems (PLA, first layer - PETG works better)  

At my wits end with extrusion problems (PLA, first layer - PETG works better)

For every successful print I've spent ten times that troubleshooting extrusion problems. Prusa Mini+ kit.

• I've disassembled, cleaned, and adjusted the extruder multiple times.
• I've changed nozzles to a brand new one (0.6mm).
• I've disassembled the hotend and cleaned it, and retightened the PTFE tube.
• I've readjusted/recalibrated the super PINDA.
• I have fresh filament.
• I've tried various temperatures 
• I've tried increasing the nozzle temperature by 5-20
• I've tried various live z adjustments
• I clean with IPA relatively regularly
• I've cleaned the PEI smooth sheet with dish soap and warm water
• Been testing with prusas USB print files

My very first print turned out crap, and then I experimented with higher temperatures, which seemed to improve things slightly (whilst causing other issues with the prints). Had intermittent decent/good results, then suddenly a subsequent print utterly fails. Troubleshoot, rinse and repeat. Lately it's pretty much instantly failing on the first layer - the PLA isn't coming out, or rather, it comes out in little dots and strings. Did a couple of petg prints on a textured bed and it worked great. 

I've pretty much given up at this point. It's a pretty big-ish job to do the refitting of the ptfe tube, and I decided to do that when everything else failed. I don't feel that I should have to do this for a product I've bought, but okay. But after retightening the ptfe tube and recalibrating the super pinda (and run all the built-in calibration tests), to my disappointment, the extruder starts clogging immediately when doing the first layer calibration.

Questions and thoughts:

• Is the built-in first layer calibration utterly useless? I mean, with different nozzle diameters, filament types, etc, how is it possible to use the same 215 degree preset for all conditions? Won't it struggle in some situations? Is it only meant for 0.4mm PLA? For example, using a larger diameter nozzle it's possible that you have to raise the temperatures a little bit. If that's the case, that means that the default first layer calibration has a high risk of clogging your nozzle. So what gives?
• Purging! Purging works absolutely fine. However, the moment the first layer starts (calibration, or regular print) everything starts clogging. How is this possible? Is the extrusion much lower during the first layer than it is during purging? The temperature is the same (215), so it can't be due to temperature.
• PETG using standard prusaslicer settings on the textured sheet works great. Only tried a couple of prints before going back to pla because I wanted to get printing PLA configured. Switched to a new 0.6mm nozzle when I went back to testing PLA.

This is the first time I get into 3d printing, and this has been a frustrating and disappointing experience. I bought this to print, not 90% troubleshoot and 10% okay-ish prints. Been struggling with it for weeks. Would never recommend this device. I get that some adjustments have to be made here and there for optimal prints, but this is actually ridiculous.