Magento 2.4 disable UI/Theme part

I’m wondering if there is some possibility to disable UI (or Frontend, or Theme) part on Magento?

The problem:

I installed magento on subdomain server.example.com and use it as headless cms. So all I need from server.example.com – it’s admin panel, graphql endpoint and media/file server.

Also I have a react app on domain example.com and it’s used for UI/Frontend as client-side application.

So, is there any chance to disable all redundant functionality on magento (like html rendering, routing, etc.)?

Thanks in advance.