I'm kind of convinced there is something else happening where the person writes down technical performance instead of, "didn't like his shoes" or whatever.
They keep pinging me every six months to re-interview too. They don't like to share why they declined though - so I don't get why they ask for me to reinterview like something magical will change without feedback.
My $0.02:
Try to press harder for feedback. I've generally had no difficulty extracting feedback on rejections, especially ones where I could be re-invited back ("well, without understanding what reasons I was passed on last time, it doesn't make much sense for either of us to invest in another round where the same issues may very well exist").
All else fails, consider mock interviews. There's paid services out there that will do this -- and you'll get detailed feedback.
Generally, if you can finish any random medium difficulty leetcode question in 30 minutes, you are at the algo bar. But there's still systems, behavioral, communication, etc.