I have this very cool project in my mind, so I'm motivated into learning a programming language, so I can develop games maybe sell it

So, in my project, I want to create this game where you are a demon buster, but you can get demons to join your side and fight alongside you, like Shin Megami Tensei series, the skill system will be like Shin Megami Tensei: IMAGINE where you raised expertises by exhaustingly using them, combining them also unlocks chain expertises. But in my game, you'll be able to furthur combine them, like magus + engineer makes the alchemist (this is only a starting thought, more will come)Also it'll be a side-scrolling, 2d game, with a combat system similar to Castlevania: Aria Of Sorrow(GBA)/Symphony of the Night(PS1), but I want to build a skill system also similar to IMAGINE, with cooldown and incatation times, launching spells and stuff.
I started looking at GameMaker, but it feels like it just doesn't meet my needs. Because I want to release updates periodically (my objective is to make this game online), putting everything into a single stand-alone file just doesn't seem to be the right way, and also I want to make different looks for every part of where equipment goes (my original project is head(hat), top(suit), bottom(pants), shoes, and gloves(armsband), then neck, earring(2), ring(4) will stay hidden), withouth having to create different sprites for every combination of equpiment.
What programming language would be ideal for me to learn?