There's a lot of advice I'd give my kids, but as far as the above statement is concerned, I would not encourage them to get into gaming or being a professional Youtuber or any of the online money-making stuff the younger generation is into these days. Would I discourage gaming in general? Hell no! I spent a lot of time playing video games as a kid, but doing it professionally--even if it's lucrative--is a waste of your brainpower. The world needs the younger generation to get into STEM fields and teaching and all of those other professions that actually benefit humanity in a significant way.
Imagine being a youtuber a twitch streamer or anything like that as the sports people of our generation. Back in our younger days we did play video games but rarely anyone made any money from it when we were kids, but people were getting millions of dollars from playing soccer and that was something we did on the streets as well. Same now with gaming as well, you could do it for free like we played soccer when we were kids, but you could also be very good and you could try your chance becoming professional as well.
As far as they study their school work and get good grades, I would say I would let them do whatever they want, I would not limit them with anything. Plus I do not really feel like forcing my kids into STEM would make any sense, if a kid wants to go to STEM field then they would help the world but if you force them to study STEM then they are not going to be help to anyone at all.