Magicka comes to mind but it was utterly unplayable single player. Maybe the sequel is better.

It feels very wizard like because you don't have a static list of spells. You have 8 elements you.can combine into spells. (It does have unlockable spells but those are sort of secondary.) So using the fire and shield elements makes a wall of flame, for example.

For just a solid combat system, hogwarts. Was really surprised. They had some solid people design and build it. Really stood out against the rest of the game which wasn't bad by any stretch just repetitive. There are some serious combat challenges too. Just make sure you play on hard. It really needed one difficulty higher tbh.

Lots of good suggestions already, adding Magicmaker as a fun build-your-own-spells game: https://store.steampowered.com/app/319250/Magicmaker/

Play Skyrim with ordinator mod that adds more spells.

Heretic and Lichdom: Battlemage