It's boring. I like Alexander, but I prefer Alec as a nickname, and I dislike Alexandra and Alexis. I prefer all the names you listed save Alexina and Alexa to plain Alex. I think it's one of the only names I regard as truly unisex, but I think it sounds wimpy on a boy and try-hard on a girl.
masculine list:
https://www.behindthename.com/pnl/191050/124079feminine list:
https://www.behindthename.com/pnl/191050/124080