How to use MVC and MVVM in one project?

The question is in subject.

I want to use Avalonia UI, that is mostly using MVVM and its documented well with MVVM examples.

And also, as i understand, MVVM is used mostly for UI, but not for the rest part of application.

However, the rest part of project is has to use MVC pattern.

The question is: how to use both patterns in one project? Is there any examples of combining both of these patterns? Or full project can be implemented by using MVVM only, and this one will be enough?

p.s. the project is like a messenger p.p.s the project is going to be made on C#

I got no results, i have stuck at this beginning architect step.