VO2 Max after covid

What about average HR - that's a good indicator that will sort of mirror your VO2 max - I find that runs that push my VO2 up tend to the lower average HR

My poor VO2max dropped a whole lot in a few days at the beginning of 2020 when I had light COVID symptoms.

So yes, I guess it’s plausible.

First couple odf runs my vo2 max dropped 3 points. Now 3 monrths later it is back where it was before covid. Had light covid. Average hr was higher too

I hit 50 before covid, and after covid it just kept dropping til it settled at 42. I’ve had chest pain ever since covid, so I took a couple of months off. I’ve made it back up to 45 and am matching the same pace, HR and running distance as before. 

I think this is indeed a common issue.
I had an nasty skin infection (so, no corona) which required to take antibiotics and to not train for 4 weeks. When re-starting training, heart rate was much higher than it used to be for comparable efforts (side effect of being sedative, weak, and antibiotics also are not really a good thing here), which made the VO2max drop from 67 to 61 more or less directly after the first training.
Now, 4 weeks later, it is recovering 1 point every two weeks, sitting at 63/64 despite feeling as strong and fast as before getting sick by now.

So: raising the Garmin VO2max value seems to be a very slow process not necessarily reflecting you current  strength (which makes sense in general as people should not get stronger super quickly, but  for sickness recovery it does not seem to work that well.)
While a lower vo2max after a sickness might be a correct/realistic estimate (Covid especially seems to have the chance to negatively affect the cardio/oxigen system), it could also be that there is a dampening factor in the algorithms which does prevent the value to raise quickly. (so that the value does not randomly jumps up and down all the time during normal / healthy periods just because you had a bad day or a bad hangover...)

I think Garmin changed their algorithm for VO2 max when they added the ability to track it for trail runs. Mine went from 66/67 down to 59/60 over the course of a couple weeks for absolutely no reason - not sick, same training, same fitness, etc. So your change may not be due to covid either and may have been an algorithm change on Garmin's side around that same time.

Vo2max is horribly bad on Garmin, and I notice they seem to change their algorithms a lot without a word, so I really wouldn't worry about it. I'd be more concerned about trends over time instead of where it guesses you are.

Mine was on 53 and every week has been dropping now to 50. Still running the same no idea what's changed

Sure, but check what else you are doing, are you going on more walks that arent really for exercise? Thats what I found was killing my VO2 max rating: recording walk distances up where I walk an older dog for a slow walk. Its been thoroughly trash though rating me anywhere from 100 to now 38 or something when the dog walks brought mine down like clockwork. I think Garmin's VO2max needs a TON of work. But if you see a constant downward pattern maybe get checked out by your MD, and if not, its just the usual..

I'd tend to agree with the point that the trends over time are most important. However, mine went from 67 to 59 in a matter of two weeks for no reason whatsoever. They had to have changed the algorithm.