It’s clearly Biblical.
No, it's not.
While there are several instances recorded in the Bible of polygamy, that is also true of every other sin. Nowhere is there approval given for polygamy.
“It’s clearly Biblical”
For those with hardness of heart, they may go for it. They might want to watch out for that eternal afterlife thing.
For all those who get attacked for “judging”, the only response needs to be concern for the other’s soul.