As they say "walk before you run". The cardio you had before Covid did not just happen overnight. You need to build back up and retrain your lungs. Doing breathing exercises everyday when you are not training is essential to recovery. Deep long inhale and exhale.

Also Congrats on the promotion!

Agree with Megaton. Covid seems to affect all of us a little different, but for me it took a couple months to really feel back to normal. Ease up a bit, maybe undulate your efforts from session to session like periodization training. If you don't allow yourself to sufficiently recover you'll end up backtracking.

Best of luck man - hope you feel better.

I've done some extensive training before I caught a covid in 2020. (3-4 times BJJ and 3 times conditioning per week). After covid, I was barely able to walk for a month, so I took a break which lasted for additional 2-3 months (because I got lazy in the meantime). When I got back to my training routine I had a feeling like I've never trained anything before... but in 2-3 months I got almost to the same state I was in before I got sick (I say "almost" because I gained 10kg overnight, so everything was much harder for me).

It took me 6 months to get my lungs back. After I recovered from covid it felt like I only had one lung. Had to skip rounds to catch my breath. Just keep rolling, rest if you have to and it will get better eventually.

Like everyone pretty much said, just take it one step at a time. One roll at a time. Also, any extra cardio you can get in, would help. Jump on a bike, go for a hike, jump rope, etc.