I've argued this many times before on my own threads and others' threads. I try to repeat the argument when necessary but it gets frustrating when nobody remembers my former versions and I have to start all over, and I'm running out of steam.
You're trying to come up with a way to square your religious beliefs in creationism with the overwhelming evidence for evolution.
You've been stripped down to accepting that the processes behind evolution actually do occur, but you've had to invent this nonsense about "only reducing genetic diversity" in order to save your religious beliefs.
You have literally zero evidence for it other than your wishful thinking.
Your entire position is a just a giant deduction - from the minimum amount of evolution that you have to accept because it is undeniable - coupled with your relentless efforts to absolutely refuse to give up your per-conceived religious beliefs in creationism.
This has lead you to the inescapable place of evolution only being able to reduce genetic diversity.
There's no reason to think it other than you have to.
Obviously you have no interest in even trying to get it.
I get it. I really do.
Its just painfully and terribly incorrect and wrong.