You may not want to know the answer to that! :D

I've always felt that äta mat sounds a bit stupid, but that's just my personal opinion.

It's as weird as in english

Right, we put commas for clarity these days, not for grammar.

You don't usually use commas before adverbs in English, either. (You can in some cases, but it's not a general rule.)

Swedish and English have common roots. My mind likes it

I'm going to add the Slovenian one: vi = you

This word order sounds formal in an odd way. It isn't totally grammatically wrong, but it's unnatural enough not to be an accepted answer.
nu is a time adverbial and those typically prefer to go at the end or start of a sentence. The kind of adverbial that typically does go in that place [= between 'äter' and 'mat' in this example] are sentence adverbials (the kind of adverbial that modifies the whole sentence or says something about the speaker's attitude to the whole sentence) inte, 'not' is a typical example, which would go there: Vi äter inte mat.

It isn't necessary like in Jag lagar mat, you can definitely say Vi äter nu (and that sounds much better, in my opinion).

Yes, that's the suggested translation.