Designing a Yu-Gi-Oh! like card game - the game phases
I'd advise against basing your system on oversimplified YGO rules. These phases that seem arbitrary were added precisely to avoid adding many exceptions and forcing players to remember them all. Having regular rules with such a gigantic deck is much better than writing exceptions on card and then have lots of pain trying to match them together.

BTW, historically first versions of YGO were much simpler and very close to what you describe, which can be seen from many legacy normal and fusion cards. Instead of the fun and dynamic game of today it was just a race to see who would draw or fuse a card with the highest ATK on the board first.