Is it fine to use my domain model as DTO (Entity Framework Core)?
I was reading about anemic data models and rich domain models in DDD. I don't want to follow DDD completely but take rather pragmatic approach and just take some concepts out of it because clean ddd seems like an overkill.
I don't want to maintain separate DTOs just for serializing and deserializing my models.

I'm similarly pragmatic as you, and I agree with you in this situation.
KISS (keep it simple &amp; stupid) applies here. If your application is not sufficiently large, a DTO layer abstraction is not necessary.
I have several colleagues who would disagree with this, this is an open discussion topic. Personally, I disagree with blindly implementing things just because it was needed in other projects. Before I implement something, I need to justify its existence in the current project.

I'm not planning to use any other ORM other than EF Core.

It's not so much about what you plan to use, but rather the chance of this changing in the future, and how prepared you want to be when it turns out you have to change it.


Is it fine if I will design my models like this and at the same time use them as my DTOs for serialization and deserialization?

Yes, as long as you're okay with the tighter coupling and don't start violating SRP by loading everything into your entity classes.
However, that is a separate discussion from whether or not you should use DTOs. You could just as well violate SRP on your DTO class.