Well the guy you mentioned is a world-class grappler, so I think you’ll get all of that if you commit to it. The ceiling is limitless, it’s a great workout and once you learn how to moderate your intensity it becomes a fairly sustainable activity once you pair up with people who can do the same.
You’re built like a truck with wrestler instincts. This is great overall, but you’re probably going to have dudes who go really hard on you. That’s rad and fun, but it’s also worthwhile to make mat time for slower rolls at an easier pace. It’s up to you to protect yourself, so tap when you need to tap. Nobody gives a fuck. It’s just training.
In the meantime, wrestle the hell out of those jiu jitsu guys. You already seem aware of the general adjustments needed to your wrestling tactics, so I’m sure you’ll pick up the new game very quickly. If you do any homework, learning about the positional hierarchy would be a good place to start. Even if you don’t know a single submission, you can just work your way up and down the ladder, or even just holding good positions. By all means, go for the submission if you see one, but you will become a terror very quickly once you can dominate the positional battle.
You’ll have guys who say you “used your strength” no matter what, so don’t worry about it. Pursue technical refinement as well as you can and be a big strong guy who knows jiu jitsu. Maybe you muscled it a bit, maybe a lot, or maybe you didn’t but it doesn’t really matter to that guy. The problem he should be worried about is that his jiu jitsu didn’t work in that situation. That’s a problem you will always have if you stick with it and train with enough good people, so work on solving it instead of complaining about a stronger guy or a more flexible guy or whatever. The thing either worked or it didn’t, and if it didn’t that’s your fault because there’s always something that can. You just didn’t do it.
One last thing I’ll mention is self-defense. It doesn’t sound like this is important, especially if you’re already set on a particular gym, but it deserves mention because of how it can shape the curriculum.
The white belt curriculum can vary wildly from one BJJ school to the next. In simple terms, I have one area school (and luckily an instructor very close by) who teach BJJ in a way that prepares you to handle violence with your bare hands in the shortest time possible (which still takes 2-3 years for most). In this school you spend a lot of time on your feet learning throws, takedowns, grip-stripping, clinch work, bearhug defense, headlock defense, rear bodylock defense and all kinds of other crap that will almost never come up in a sport BJJ match. You also learn groundwork that is applicable in a fight and do lots of rolling, but lots of time on that other stuff too. No time is spent teaching sport-only techniques at this level. Only high-percentage fight techniques.
The other schools I’ve trained at generally leave some or even most of that stuff out, and instead focus the mat time on playing the game. This will still get you ahead when it comes to violence, but it’s a different enough use of the mat time at the white belt level that it’s almost an entirely different martial art. I enjoy my mat time here too, but you aren’t really learning how to fight. You’re learning how to roll, which is fun as shit and still pretty damn useful if a fight goes to the ground.
Some schools are probably in-between those extremes. One school in my area teaches BJJ mostly as a sport but you can do the MMA stuff to and learn striking and takedowns, etc in the same gym.
I don’t know anything about your guy other than he’s a world-class grappling competitor. I’m sure his academy is great, but all instructors will have differences on what white belts learn. Whether this is important to you or not, I would still advise you to try out a few gyms in the area if any of them are viable options for you. Most do first class free, so there’s really no downside. Talk to the instructors if you get a chance. Like you said, find your “tribe” and train with people of like mind.
Otherwise, just rip it and have fun. You’ll be a beast. Enjoy being a beast.