Working on a home brew Wizard subclass based on yugioh cards for a player of mine, was wondering if anyone could give me some pointers or let me know if anything seems too powerful.

He has a 40 card deck made of mainly old cards. The idea behind the deck is it’s shuffled at the end of every rest and he uses spell slots to draw cards. He has one more spell slot of every level than a regular wizard. If he draws a monster he has to make an intelligence roll and score above the monster’s level times two (average in his deck is level 4). If he succeeds the monster is summoned (I’m working on a stat block for each card in his deck, glad the campaign won’t be starting for around 2 weeks), on a failed save the monster goes to the discard pile. He can only have one monster summoned at a time and it acts almost like a Ranger’s Beast companion (only a bit stronger). If he draws a spell or Trap he has to roll an intelligence roll, if he succeeds then an effect based on the spells effect in the game will happen (Pot if Greed will give him two more 1st level spell slots, Monster Reborn will return a Monster from the discard pile to his hand, Mirror Force will cast a shield spell as well as give him or his monster an attack of opportunity)

At second level you lose the ability to cast any spell apart from cantrips, instead gaining the ability to use your spells slots to draw cards from your deck equal to the spell slot level.

At sixth level I want to give his monsters a damage boost equal to his intelligence modifier but I’m not sure if that would be better as a level 10 ability, maybe give his melee monsters a second attack and his ranged monsters the intelligence bonus? If this is better as level 10 maybe I’ll let him pick a signature monster that he can call to his hand by using a 3rd level spell slot.

At level 10 I plan on letting him use two monsters at once as well as letting him reroll a failed summon once per long rest.

And I don’t have an idea for 14th level yet, maybe letting him start with a hand of three cards each combat?

This will be my first homebrew subclass so any help is super appreciated.

Edit: Here is the Google Docs link to view all the monsters I've worked through so far. https://docs.google.com/spreadsheets/d/148J8DGoXF_RwXlknjGlA6kaDQDRQvkrqWn9IFeKmtPo/edit?usp=sharing