The only certification I have is from the Kansas City Barbeque Society, allowing me to act as a judge in BBQ competitions.
Things are probably different nowadays, but at least 15-25 years ago you could just apply for IT jobs and if someone lied about their skills it would hopefully show during the technical interviews. I don't know if that counts as getting in very early.
Ahh, I thought you meant you had a 0.2mm nozzle, but now I see you probably meant layer height.
Moisture absorbtion is rarely a problem with PLA, but hopefully dehydration won't hurt, as long as you don't accidentally overheat it and it deforms. I've left rolls of PLA out in the open for 6 months without noticing any deterioration. Both your filaments used to print fine, and then the oozing spontaneously started with both of them?
2mm retraction should be more than enough for a direct drive extruder.