I agree with this. When I had “Coofid” I sat in my black leather interior car in the September sun and baked for about an hour. That in conjunction with hot/cold shower therapy helped a lot. I also had a cold somewhat recently, the bull crap doctors gave me nothing but charged me $100. Got over it in a few days with RAW garlic, echinacea tea, VIT D and lots of rest and fluids. Shouldn’t have even wasted my time with these clown doctors anymore.The first phase of the treatment is to realize that there's no covid illness. It's what we call Flu and flu is nothing but spontaneous detoxification. So anything which assist this process is beneficial.
Up to this day I haven't had a flu for more that 20 years since I started using sauna therapy which assist detoxification through the skin via sweating. When I was growing up we didn't have a sauna but we did encouraged sweating by putting your legs in a bucket full of hot water and people would through lots of blankets over your entire body to induce the process. It worked every time.
You need to sweat it out and it's not a fictional virus but the toxins accumulated inside. We wear too much clothes during the winter and the skin's pores get congested. This and other factors explain why we "get" the flu during this period.