First up, DON'T QUIT YOUR DAY JOB! I don't mean to be harsh up front, but you're competing with many others for views & viewers... so you should temper your expectations for the uphill battle you're about to face.
Second, consider if you want to do raw, live broadcast (w/ local recording) OR a more refined pre-recorded video. Live broadcasts are generally easier to do & have lower expectations, but you have to exercise a bit more restraint with comments & actions since you don't have the option to "edit in post(production)", where you can remove stuff that's more objectionable in recorded content.
This also means that you'll have to be on your "best behavior" here... which means that you'll want to keep your language fairly clean (keeping language no higher than rated "PG-13" on average), avoid offensive content & avoid poor gaming behaviors (like Rage Quitting in online mulitplayer games).
Third, consider HOW you're doing your channel / broadcast. Are you going for "professional" & more serious tone (trying your best) OR more of an "entertainer" where you're just trying to have fun with the game & your viewers. There's various audiences looking for different content by comparison.
As you're going more sports based (or what I end to call "Bro Games"), you'll likely want to go more professional than entertainer here.
Finally, if you're considering live broadcasts, consider your potential WORLDWIDE AUDIENCE. If you're broadcasting late-night (like 12:00 - 6:00 AM local time), consider where in the world it'll be "Prime Time" (like 6:00 - 9:00 PM) or when you're looking for an audience (if you're shooting for morning people, daytime / afternoon audience, ect.) from region worldwide.
As for platforms, Twitch is generally the largest platform for live streaming. It's the easiest to set up, but you're going to be competing with major broadcasters for audiences... which can make it harder to make a name for yourself as you'll likely get buried under more popular broadcasters.
YouTube is fairly decent as well, but you're going to be competing with recorded videos on top of live broadcasts... which can make it harder to be noticed.
Mixer is a bit too obscure to get a large audience, but it may be easier to get an audience (what few people may watch there) by comparison.
There may be other platforms as well (like NicoNico in Japan, which is their major online broadcasting service that isn't limited to just gaming), but you'll have to deal with the language barrier(s) along the way. You may have issues find such services as well, since other countries may keep it a secret to themselves.
Hope this sheds some light on the subject to so you have make better-informed choices.