Take a look at the Ansible playbook for Lemmy as it Does exactly this. Installing one Nginx on the host system and using one in docker. You can probably pull configuration examples from it.

I don’t use the tool you mentioned above. but I can recommend graylog for this. For emails just use the Mailserver form proton or Google. Setting one up is a loot of work and even then gets probably banned by all major ones…

Docker isnt build to run these type of Programms. You should look into sandbox environments to test these apps.