Completely anecdotally, but my cardio got destroyed the moment I began cutting weight and never came back even though it's been a decade. I used to play full rugby, soccer, basketball, etc., games without getting tired. Same with lifting weights, long intense sessions were easily doable.
The year I added wrestling to the mix and had to cut weight every single sport my cardio went to shit, even after my wrestling season was over or I'd have no tournaments near my other sports or lifting sessions. I'd just hit the wall and feel weak very quickly. And the most I was ever cutting was like 22lbs, which honestly was an easy cut for me. The cutting never felt overly excessive, and I still remember one tournament breezing into my weigh in perfectly on weight meanwhile one team mate was running in the hallways in a garbage bag. I went and got Subway after weighing in meanwhile my coach sent me a pic of him now sprinting on a bike lol.
It's still the same to this day. I no longer run as it just never improved. 5k or 20k felt the same to me. Same with a long weight session or a short session, so now I just spread my sessions across multiple days to get in and out before I'm wiped. And it's weird as I can look at my numbers and see that actually yes, in the areas I've focused on I definitely am stronger and have better than before this. Numbers wise there's nothing wrong, my body can apply and adapt to progressive overload just fine.
But the wall still hits and afterwards it's just all mental as you're not actually getting that much more tired. I know the exact look and feeling you see on some fighters who "gas" but then still manage to go the full distance.