Out to lunch yesterday, our server, a rather cute late 20s gal, mentioned she'd had COVID. I later asked her how bad it was, and she said bad, it was a year ago and the docs misdiagnosed it as Strep, which she knew was wrong. She went back a few days later still very sick and they knew what it was. She said it took her two weeks to recover most of the way. My son had a similar illness, so it does hit younger folks hard at times.
It could be some early variant was harder on younger folks, not sure about that at all.