I’ve upgraded to testing 23.0.4 from 22.2.7. I had 502 bad gateway because there was no nextcloud.conf in /etc/php/8.0/fpm/pool.d/. I copied the one from /php/7.3/ and replaced by the correct values and now it works great ! 
I don’t know how to prevent this ?
The upgrade took me not less than 26 hours 45 minutes 
If it interest you, here are the logs : https://paste.yunohost.org/raw/urucisehuf
Everything’s fine, but there are a lot of chown of Nextcloud final_path and Nextcloud data_directory and it takes 4-5 hours for each.