Taubah from making gheebat (backbiting)

Sometime ago I backbit and engaged in alot of idle talk about alot of people as I was not much of a practicing Muslim. Those people are not aware of my backbiting. Now I have turned back to Allah; I have repented alot and repented sincerely and realized my mistake.

It turns out that the people I used to backbite are alot since I dont remember them all can I make dua generally for all people that I backbit without taking their names or mentioning them? like "Ya Allah, forgive all the people that I backbit and raise them in ranks".

Also, will Allah Ta'ala forgive me? I am afraid if I tell those people that I backbit them it will cause some hatred in their hearts for me. So i decided not to approach them and repented sincerely.