You're wrong here, Twitch doesn't ban gambling streamer e.g. Drake because he's gambling on sport betting, not luck based games e.g. slots, roulette, dice etc. The problem is Twitch banning the site e.g. Stake, if Stake separate his casino site and sportsbook site, of course they will can advertise on Twitch.

Youtube is worst than Twitch, so I don't think there's another good platform for Drake except Twitch since the other platforms doesn't popular.