I see a log for the failing backup process and after that a second one for a fresh install. Do you have any other back to restore or do you prefer to start with a fresh installation ?
Could you check if the folder /var/www/immich is really missing with sudo ls -alih /var/www/immich?
if yes can you try to update without creating a backup with sudo yunohost app upgrade immich -u https://github.com/YunoHost-Apps/immich_ynh --no-safety-backup?
yes that’s a good move.
now sudo rm -f /swap_immich and after that sudo yunohost app upgrade immich -u https://github.com/YunoHost-Apps/immich_ynh --no-safety-backup