Unity supports C# - so if you're determined to use Unity ...
All the top game development will teach you their language - it isn't necessary to formally go learn a language beyond them - at least not at first. Possibly later if you want to write complex games.
I'd recommend you download a few free or trial versions and play around with them before deciding: https://itch.io/game-development/engines
Some are easier than others, and some are more suited to a specific kind of game - it depends on what you want to do.