“Magic system” is a bit of an oxymoron imo. The problem with having hard rules for magic is that that’s not magic, that’s science. You just end up with a world with slightly different physical laws.

Technology can be interesting on its own but a deep understanding of the underlying mechanics kills the magic. A rock that lets you talk with someone over great distance is magic but if you explain it as manipulating imperceptible vibrations in the air you just have a radio.