I think you’ll find that each game you play helps you develop different areas of your skill set as you’re often forced to work on different things to succeed in them. Also, many fighting games feature similar, repeating elements and so your knowledge and practice of those things can be immediately transferred over almost directly and still remain mostly intact.; we call these things “fundamentals.”
You can be developing yourself generally no matter what you’re playing: this would be things like your mindset and nerves, mental toughness and agility, your dexterity, your execution, your reaction speed, etc. In addition, playing multiple games can grant you a unique or broadened perspective for any one of those game; this is useful because the basis of all counter-strategy is creative problem solving.
To top it all off, as you explore a game and work to increase your abilities at it, you are familiarizing yourself with your own learning process and optimizing its efficiency; you’re learning to learn better/faster/better. You will gradually find key ideas more easily, pick up new concepts more quickly, see more depth in situations, produce more accurate analyses, and even have an easier time memorizing and recalling the details.
An extremely common hurdle encountered by people who have just recently started playing multiple games is that playing one game makes them worse at another. Be aware that you will likely feel this at first. It will be quickly and completely overcome as you build up your experience in and understanding of each game.
Here are some threads from last couple of years, listed from newest to oldest, that all contain ideas from which you may find benefit. You may have to
Playing more than 1 fighting game competitively?
Maintaining skill level over multiple games?
Who is considered the better player?
Is it a bad idea to enter many tournaments at once?
(I sound so stupid in all of my older posts, hahaha.)
I should also add that there is absolutely nothing wrong with sticking to one and only one game. I won’t go into any details about it but, in terms of increasing your prowess in one particular game, focusing all of your energies into only that one game obviously carries its advantages. As long as you’re enjoying yourself, it can only be a good thing. They call those players “specialists” for a reason.
Uhh, so basically just play what you want and things will work out for you. The more you play, the better you get.