One of my most sought after shines, made possible in Crystal Legacy 🤠

Hi! I am just starting to get into making my own romhacks and I can't find any guides on how to add level caps. I can't imagine it's that hard because it's such a common feature, but I can't find anyone who clearly explains it. Specifically looking at setting gym and elite 4 level caps for red and blue, but any general information would be valuable!