anonymous link to layouts

I'm wondering if this is a good approach. I want to use a link from the layouts folder to probe the individual SharePoint servers for health. For example, a link like this:

https://sharepoint_on_prem/_layouts/15/myCustomFolder/images/helloWorld.txt

It will be used by outside scripts, load balancers, health tracking software, etc.

The SharePoint application is not set up to allow anonymous currently. I'm thinking to make web.config edits and have AAM. I'll add an AAM anonymous site, and in the web.config I will block mostly everything outside of the target url.

I think that I can probably even allow a specific full /_api/ path that check what comes back from the search service to make sure that's working and fully indexed.