If you want a 100k+ subreddit then you are looking for https://www.reddit.com/r/TeamfightTactics/ . Our sub here is more niche and strict.

Also if you want to make a own tournament with a game that doesn't provide you with a spactator mode, this doesn't work so well. Early League of legends didn't had one but they had a workaround.

The game doesn't need to grow. There are around 1 million ranked account/players in set 2 on each NA and EUW. What the game needs is not to die. But what is happening is that twitch viewers decline and popular streamers ditch tft for hearthstone battlegrounds. While alot of players here report that their friends barely play and alot of ppl just wait for next set because they don't enjoy set 2. The game will have a new audience anyway with mobile coming out. I doubt that inviting a player like dogdog or tidesoftimes to a invitational tournament will make tft player numbers spike in anyway.