I think for many people who want to selfhost a search engine, a metasearch engine like SearX (and forks) are not what they are looking for.

It would be really nice if SearxNg could query an internal index instead of relying on 3rd party search engines.

As someone who runs multiple email servers, this is exactly how it works.

Some email providers will randomly or purposely block emails I sent to them. I get arbitrary blocks or dropped emails on sent emails.