I'm sorry to hear you're going through that. It sounds like you are suffering from Long COVID. Have you sought medical help? Are there any Long COVID support networks in your area? Also, the vaccine can sometimes reduce the severity of Long COVID, so if you're eligible for your next booster you could try that as well.
Unfortunately Long COVID (and particularly its intersection with neurodivergence) is poorly understood, but seems to be related to ME/CFS. An essential part of managing either of those is pacing yourself (this also applies to autistic burnout, which I am slowly climbing out of), which can be really challenging to implement. The basics such as sleep, nutrition and exercise (just don't overdo it! Pushing yourself will make it worse) are also important.
This is very true. Several people who are close to me have mentioned feeling exactly this - that they had some personality defect, when in reality they were neurodivergent.