Please... as posted here many times, he had a single positive test for coronavirus in a sequence of negative tests. He isolated after the positive test and returned to training after the second negative, as per the protocol at the time. They are not COVID-19 tests, they are coronavirus tests and the tests are notoriously unreliable. That in a period of about 10 days. If he had developed the disease COVID-19, he'd hardly have recovered within a few days and got training again.
My youngest son had exactly the same. After Christmas, he was in hospital due to a back injury during which he had 2 coronavirus tests, both negative. A few days later, due to possible contact, he had another test – positive, so self-isolated. After a few more days, he was recalled to hospital for a scan and was required to take another test – negative. He's since had 3 or 4 tests – all negative. He's had no symptoms of COVID-19 and the hospital tells him that a random positive in a sequence of negatives is quite common.
Bryan has lost form but he's also lost the performances of his attacking partners who occupied a lot of defenders and allowed him space which he's not getting now. Over half the way though the season and, of the 3 wide attackers, he's still the one with the greatest number of goal contributions (goals + assists). Working a perm of any two from three is far from ideal but that's what we've got and they could all do with a break. He needs a break from us, too, not scapegoating, and I'm sure he'll continue to provide those contributions.