I have fought a handful of people that were actively taking steroids and were open about it.
Sparring those people was very very different and I’ve done thousands of rounds of sparring.
One thing you learn rolling with alot of blackbelts is they are happy to match your pace all day, everyday; If you want to flow roll, they are down, if you want a fight to the death, they are also down.
Periodically train with people that are much bigger than you and much smaller than you. With much much heavier guys I only train with them every couple months or so but its good to spar them to keep things fresh and grounded in reality.