That for sure that is not overwater .....
Happy Frog is a light mix and it will require fertilizer to take a plant much past 30 days, works fine for lettuce and radishes but a demanding plant, not so much ..... Good starter soil as it is heavy in microbio stuff but not for an entire grow .....
Also HF maybe retaining too much moisture as it is heavy peat based soil that holds moisture so there maybe a double issue with both water and nutrients .... But I’m guessing, no experience to back my thought up, it’s just a thought ....
Suspect you’ll be fighting what to give the plant for entire grow, unfortunately .....
Start again and stay with a well known medium and follow feeding schedule but then some say you can save but yield maybe minimum and airy, cut your losses are my thoughts .....
Hate when stuff like this happens, best of luck!
Here’s a novel idea, try Living Soil!