The title may seem a bit weird but i'll try my best to phrase the question properly. Currently, I am trying to add a racial feature that works similar to how items that cast using charge work. The racial feature lets you pick two spells that fit the criteria and you can cast them using pseudo-spell slots meaning they share the amount of times they can be used similar to class-based spell casting. The problem is that when i try to make this work, each spell can be cast X amount of times per long rest instead of Spell 1 and Spell 2 at a cost of one charge each can be cast using one of X total charges as part of the feature as if they were spell slots. 

Does anyone know how to do this or if its possible?

Might have to make a Feat like Fey Touched to make it work. 

I think you could change one of the races in Monsters of the Multiverse that has racial spells to the ones you want. 

Don’t attach any uses to the spells and instead create an action attached to that racial trait that has Limited Uses attached to it. The spells will display as “At Will,” but if they get tapped/clicked the sidebar will slide out and the player should be able to check off the limited uses attached to the trait.