I still see an “access denied” error in the log file. If you want to access Redis using a socket, you only need to set 'port' => 0, in the Nextcloud configuration but NOT in the Redis configuration itself.
Additionally you have to make sure that the web server user, e.g. www-data, is allowed to access the socket file. If a assume that the Redis daemon is started under the user “redis” with group “redis” you should make sure that the web servers user is a member of that group too.
How this need to be done in detailed has been described in this forum multiple times. See e.g.