Using a new TemplateContext won’t cache the compiled page, also if using TemplatePagesFeature in DebugMode will check for modified pages and reload them.
Are you running into any issues by just registering TemplatePagesFeature that you want it limited to a specific sub directory? Note you can easily ignore .html pages or configure it to use a different.htm extension with:
Mainly because I am not looking to host it as part of the webapp exactly, and have different format templates in different folders (xml, html, md…) for various scenarios. I guess in that case it will prob be best to use multiple Template Contexts and invoked from custom service routes.