Anecdotal evidence of course, but my daughter’s friend, who is in her twenties, has no sense of smell and almost no sense of taste since she had COVID in 2021. A neighbor of mine, who was in excellent health when he caught it in January 2021, still has an altered sense of taste and smell, and heart problems. I haven’t observed oxygen tanks, but I’m not particularly surprised.
Physics Girl has a really severe case of long COVID. She's 34. She has extreme fatigue and can't make videos anymore. There have been a few updates from other youtubers she's friends with over the last two years: