How to change the .onion domain on the server if there is no privat_key in the /var/lib/tor/hidden_service folder?

Question

Tor

Good time, friends!
I needed a private host here and I decided to put Tor on the server. I immediately wanted to change the .onion domain to a readable one. I generated a new one, shorter ( Cygwin + Scallion ) and registered it in the VestaCP panel, directing it to localhost . I also corrected the location in Nginx by entering a redirect to localhost:80 . Rebooted the Nginx , Tor services and tried to access the automatically generated .onion domain from the file /var/lib/tor/hidden_service/hostname - a test page is displayed, everything is OK! Well, let me think I will replace the generated .onion with the default domain. I stopped the Tor service and got into the /var/lib/tor/hidden_service folder for the privat_key key , and this is what I saw:

It turns out that the old method with replacing the key in the privat_key file of the /var/lib/tor/hidden_service folder is no longer suitable?..
Searches on the global web did not lead to positive results - the old solution fell out everywhere.
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Apparently this is due to the new encryption standard tor_v3 .
I need your help , I'm sure that someone already knows how to win this.