Your patch file is at incorrect location, folder structure should be like -
in your case error is here -
put config folder inside your environment folder, such as sitecoreruntime > production > config > Sitecore.IdentityServer.Host.xml
Caching is stored in memory, not in database or files.
You can check the cache sizes from /sitecore/admin/cache.aspx, which will let you check the max size they have been configured and how much they have been filled.
There is nothing out of the box which allows you to inspect the cache and what is being stored in them, but generally speaking for item caches ...
There are probably hundreds of examples where using the z prefix can be seen. This is a convention followed to ensure that the patch is applied last.
Before Sitecore 9, using a folder or a file prefix with z was the best way to get your changes applied in the desired order.
After Sitecore 9, there was introduced a new feature to apply configuration ...
Have you checked final values for this settings in showconfig.aspx I think your file is not getting patched properly.
You can use below steps.
Create a Config file with appropriate name, by using below lines.