Can I use a Joomla website to access non- Joomla apps and services?

I am in the process of learning Joomla I wish to develop a Joomla website, but I need to be able to:

  1. have Joomla navigation links and forms access a REST API served by a Spring Boot service
  2. interface with a React or Angular- based SPA
  3. Use Spring Security for authenticating/authorizing users of a Joomla website

Is it possible for a Joomla site to work with non- Joomla apps and services? If it is, how would one do this?