Post COVID for 21 months now and still declining

Hello,
I'm a mid-40s male in good health (or was). I contracted COVID in Oct 2020 and never recovered from it. I had what they called a "mild" case where my blood oxygen level didn't drop below 90% and I wasn't hospitalized. I had a fever for about two weeks, migraines, and numerous varying symptoms over that period of isolation. Once I finally got out of isolation, I still encountered heavy fatigue, muscle weakness, and heavy inflammation. I teach computer science and cybersecurity at a small university and consult on the side. I was missing 2-3 days of class a week due to an inability to function well enough to lecture. I was sent to the ER twice, once due to possible stroke and again for a kidney stone (never had one before in my life).

I was vaccinated in the Spring of 2021 because the stories of it improving Long COVID suffering, it didn't. A couple months later in June, I started to relapse badly, and have been slowly declining since. I had to withdraw from my doctorate program because I was unable to keep up with the work as I struggle to keep a thought for more than a couple minutes. This is also impacting lesson planning, lecturing, consulting, etc.

Currently, I am struggling to move very far physically. I try to walk for 20 min a couple times a week, but it takes 2-3 days to recover from it. My body is constantly in pain from the inflammation (6 or 7 on a scale of 1-10), with spikes from time to time. I struggle to walk, type, or perform many activities. High temperatures amplify the pain and weakness, so this summer has been far from relaxing. I've had to use a cane to walk, but my grip and arm strength is not good, so it's not much of a benefit. I'm used to working 8-10hrs a day and right now am lucky to get 2-4hrs in a day. I'm the sole source of income for my family so I can't just stop and rest until better.

I've been visiting the Vanderbilt Adult Post-Acute COVID clinic for over a year now. We've tried many different treatments, mostly wholistic focused, but with minimal success. All the treatments that have worked for other patients in the program have not shown noticeable improvements for me. I'm running out of ideas for things to try. I have to resume teaching in a month and I'm not sure how I'm going to survive the semester in my current state.

I'm on a base set of a good pro-biotic, Vit B complex, Vit C, Vit D, baby aspirin, one or two other supplements. I've tried PEA supplements, NMN supplements, Cortisol managers, and others. We tried a common steroid to try and alleviate some of the pain from inflammation, but it didn't prove any benefit, only major side effects.

Any ideas of things that may help are welcome.