I am sorry to hear that your are experiencing this after having a surgery intended to reduce your pain. In the best of circumstances, the cause of neuropathy often remains a mystery. Now, it is hard to know what is due to Covid, and what is due to subsequent events like surgery... the question is whether it really makes any difference because you still need to deal with the symptoms.

It is important to remember that nerves are affected in the TKR surgery, some directly, others can become irritated. Literature regarding post-surgical neuropathy predates Covid and addresses the issue. For the most part, it was concluded that symptoms would ease over time for nearly all people.

Covid and post-Covid long haul syndrome are so new that definitive answers are scarce as of yet, but there are numerous studies underway. Roughly 20% of people do experience some nerve symptoms after a Covid infection, ranging from headaches to numbness to full-blown neuropathy.

In general, any neuropathy after knee surgery, whether numbness, tingling or pain can be a sign of nerves damaged or nerves healing. Nerves heal very slowly, and there is no way to rush things. After ACL/MCL surgery due to an athletic injury, it took an entire year for the nerves to completely and my knee and foot to fell normal. In one of my hip surgeries, the recovery was also very slow, even though in others, I was fine in 3-4 months.

You are in early days with respect to recovery, but if you are not getting good answers from your surgeon, perhaps you want to consult your primary provider or a neurologist for more help.
Sue