Similare tag manage

Hello,

We have a problem to solve:
We would like to merge similar tags that are identical but concidered as unique by WP (e.g. upper/lower case letter, accent, spelling mistake,…).

It’s a colossal job if we have to do everything by hand. So do you have an idea automated solution to detect similar duplicates to merge them?

Or maybe another plugin…

Thank you very much