Well, I can't take credits for that 😅
I understand very little about training and development, but searching in some FM related pages, I found the training and youth development guide from a certain JonasMorais very, very useful.
https://www.fmscout.com/a-fm24-training-guide-and-schedules-by-jonasmorais.html
The link is for his training schedules, but there's also a link to his youth development guide in the same article.
The filters for searching the right staff are very simple. I always look for staff who, at least, has a driven mentality, and preferred formations most close to I've been setting up my team. Also the attributes of determination, motivating and discipline are at least 14 (13 for my youth staff)
About that, I had to be more flexible about the attributes for the under 19 staff at the first 2 seasons. But revamped it completely since the 3rd season.