i recommend trying all three and seeing which one you personally prefer. they all have their pros and cons. like, TikTok will force ppl to see your livestreams, which means discoverability is pretty high. YouTube will pushes to thousands of ppl, depending on the stream. and Twitch doesnt push but has categories for games and stuff ppl click on to find streamer. so when you get a viewer its because they were in interested in watching you play the game or make art, whatever.