Google account hacked! How do I get it back?

Be
4

Last night I discovered that my YouTube channel had suddenly been renamed from "Zap" to "Live News". When I tried to log in, it didn't work. It said the password was changed 7 hours ago (now it's 42 hours).
"Reset password" did not work either because Google classifies my computer as an unknown device. This was also not possible via iPhone or my laptop. Although my Google account has always been connected to the devices mentioned. I certainly haven't changed the location either.

The help pages from Google do not help me any further and contacting support via e-mail or phone unfortunately doesn't help at all.

In addition, the person was able to change the recovery email (email address from my father) and also the cell phone number (my own) for recovery.

My linked e-mail address seems to be still working and still linked to the channel, because when I register I get the message "The password was changed X hours ago" and the profile picture is still the same.

Unfortunately, I had almost everything linked to my Gmail, including private things. Feels like everything I've ever used online. The great thing about it when I want to change passwords or the email… First, send an email to my hacked account, which is actually to be confirmed. Great.

I very much hope that someone here can help me.

Link to "my" channel: https://www.google.com/...uZ1-GfA5fk

Ca

How was it possible to change the recovery email? To do this, he should actually have access to this e-mail, because normally the code / link is sent there, there may be other ways to identify you, e.g. Security questions, unfortunately I haven't had any good experiences with Google support

Be

The help page brings me nothing…

Be

I don't know how that was possible. My father must have received a notification that his email can no longer be used for recovery. That's it. And the security issues… I don't get that far because Google then tells me that my devices are unknown and that I should try later. In other words: You have to activate it. Which the hacker is definitely not planning to do.