He might be the wrestler with the most inflated case for an all-time great imo. Someone who "feels" different compared to the rest of the roster in large part due to working part-time and not sticking around long enough on TV for creative to screw him up. It's a bonus when his mouthpiece is one of the best to ever cut a promo in Paul Heyman. The majority of matches since returning tend to be derivative and heavily reliant on how his opponents can sell the damage of his frankly limited offense while playing the face in peril. It's not surprising then that his best work is often against some of the best talent on the roster at the time who can play to that strength of his (Bryan, Styles, Mysterio, Reigns at WM31, etc.)
It's also not like his misses boil down to him being unmotivated. We're talking about a guy who got to work several marquee matches against guys like The Undertaker and heir to the devil's throne Triple H; legends who are respected by the vast majority of wrestlers. If this dude really couldn't have cared less working with those guys, would be have still been employed with the company up until just last year? Even if we do entertain the idea, it's not a good excuse by any means, especially given the relatively small body of work he had from 2012-2020.
Note: I'm aware that my tone can come across as confronting or condescending, so I wanted to add here that I understand why people might hold Lesnar in high regard. It's not like he was in the Top 100 in 2016 for no reason. But when I've seen him show up these last few years, I don't see him as a guy who held up as this special attraction, nor as someone who was beneficial for the WWE. Rather, he's one of the very few to benefit at the expense of modern-day WWE, both the talent and product.