Best practice for CSS management in WordPress: a last file or multiple page-specific files?

I have analyzed different WordPress websites and try to find the best way to manage CSS files -both for performance and for maintainability. I have noticed that many WordPress themes and sites tend to use a single, combined CSS file that includes all global styles, components and page-specific styles in one place. This raises a few important questions for me:

• Is the use of a final CSS file considered a best practice in WordPress development?

• Would it be better (in terms of performance or code -underhandability) to split CSS into multiple files -for example a Global Stylesheet + One CSS file per page or template?

• There are disadvantages of performance on splitting CSS files in
  WordPress, such as more HTTP requests or problems with caching?

• Why do most WordPress themes prefer the single file approach? Is it it then
  Due to compatibility with caching -plug -ins, CDNs or something
  otherwise?

I would really appreciate hearing from experienced developers and theme makers. If you have tested both methods or have insight into performance effects (eg Core web vitals, FCP, etc.), that would be incredibly useful.

Thank you in advance for your advice and detailed explanation!