New Life in the World of Magic

Hey my readers thank you for the support and I apologize for dropping off the map. I've read the reviews and I can't help but agree with some of the points that the story needs to rewritten and that I have made the mc way to strong for a first year.

I plan on starting new with my Harry Potter FF with less plot holes and a different backstory but I'm just a little bit of trouble figuring out how the magic system should work. I want to make the increase of power understandable with the characters as Harry Potter itself never really put a clear cut reasoning behind how magic really functions.

Options:

Core: thinking of making it a color code kinda thing making white be the most pure kinda magic a wizard can hold.

Mana viens: which will be the wizard drawing off the magic of the world, drawing more they can handle will exhausted them. Really talent, Rituals, and aging to maturity are the only way to increase this.

And lastly I would like to hear ideas from you all. There is also magic circles around the heart that you read about in most fantasy tropes but I'm not exactly sure how to work that into Harry Potter. Anyway please help me out here as the magic system set up really has me stumped as I really want to go with something that isn't crazy.