For example, invest 5 million rubles in servers, marketing, and creating such a platform. Organize all sorts of tournaments, fill the site with content. If two people want to compete against each other, they each put 300 rubles into the bank. The organizer/platform takes 10% for itself, as a kind of judging fee, cheat detection, and other perks, and the rest goes to the winner. Honestly, I would play in such matches.

What's the problem with creating such a platform? Local gurus have thought about this a thousand times. What is the main obstacle to this process? Is it that people don't pay? Have you checked this? Is there no one to take it seriously? Is there a lack of necessary investment? Are there no prospects in this direction for HMM?

It seems you answered yourself. You have 5 million – invest it. And to attract other people's investments – again, go for it: draw up a business plan, calculate monetization and payback periods. At the same time, read the legislation regarding gambling. That is, all this activity related to games for money will have to be carried out through a foreign country. I assure you, 5 million, when recalculated with all the associated hassles, will increase many times over. And there isn't a million-strong audience ready to pay.
You yourself write that you are not ready to donate for streams and pay for the development and support of the game: how nice – and make it all for free.... And 10 percent commission in a duel game is 20 percent of the winnings. And why would players pay such a huge percentage to intermediaries when they can agree directly?