@Naveen
Skip the backup or create a dummy /etc/php/8.3/fpm/pool.d/nextcloud.conf and run the upgrade.
[nextcloud]
user = nextcloud
group = nextcloud
chdir = /var/www/nextcloud
listen = /var/run/php/php8.3-fpm-nextcloud.sock
listen.owner = www-data
listen.group = www-data
pm = ondemand
pm.max_children = 16
pm.max_requests = 500
request_terminate_timeout = 1d
pm.process_idle_timeout = 10s
php_admin_value[upload_max_filesize] = 10G
php_admin_value[post_max_size] = 10G
php_admin_value[memory_limit] = 512M
; Additional php.ini defines, specific to this pool of workers.
env[PATH] = $PATH
env[LANG] = $LANG
env[LC_ALL] = $LANG
php_value[default_charset] = UTF-8
; OPcache is already activated by default
; php_value[opcache.enable]=1
; The following parameters are nevertheless recommended for Nextcloud
; see here: https://docs.nextcloud.com/server/20/admin_manual/installation/server_tuning.html#enable-php-opcache
php_value[opcache.enable_cli]=1
php_value[opcache.interned_strings_buffer]=32
php_value[opcache.max_accelerated_files]=10000
php_value[opcache.memory_consumption]=128
php_value[opcache.save_comments]=1
php_value[opcache.revalidate_freq]=60
; https://docs.nextcloud.com/server/latest/admin_manual/configuration_files/big_file_upload_configuration.html#configuring-php
php_value[output_buffering]=0
; https://docs.nextcloud.com/server/latest/admin_manual/configuration_server/caching_configuration.html#id1
php_value[apc.enabled]=1
php_value[apc.enable_cli]=1