Over feeding (10 different fertilizers!!!) and under watering has lead to o build up of nutrient salts in the substrate, causing this burning.
Watering to run off each time you irrigate is vital for overall health.
This is too far advnced and the plants too close to being ready, that there is nothing you can do to fix this before harvest time.
Had you asked this question 2-3 weeks ago when the problem probably first appeared, there may have been a chance to stop it getting worse, but now is too late.