Would you guys want to mix the gimmicks (mega, dynamax, tera, etc), or have them be separate matchmaking when they drop?

Someone's probably asked this before, but basically title. I'm kind of a beginner to competitive pokemon, and I'm really only familiar with megas and teras. Do you think it'll be difficult to balance the game if multiple of the mentioned mechanics are able to co-exist in the same game, or do you think it'll be fine? I personally have no clue, so I'm curious what you guys think is the best for the game competitively. Should I be able to mega-evolve while my opponent dynamaxes, or would something like this be unbalanced and unfair for one side?