Is it worth to use MUI/ChakraUI with NextJS?

I am quite new to NextJS and I were developing apps using React and Django before. So please correct me if I am miss understanding some points. I have some questions about NextJS, however I searched a lot but couldn’t find my clear answers and they confused me.

1- Is NextJS really suitable for backend? I searched about this; there are two answers (yes it is full-stack/No, better to use other backend specific frameworks)

2- Doesn’t using MUI/ChakraUI breaks the NextJS concept? because when the site is based on MUI every component is a client component right? So, what ever I am going to show the user is a client component that it becomes something like pure react.