Learning Polish but not focusing on the grammar, good idea?

You mean The Natural Approach method?

Yes, something more natural. I never learned proper French as in hs they focused too much on grammar.

Believe me, German grammar is much more complicated than French grammar.

Nobody can say it in a straightforward way until they go through the whole course. To be able to compare, they also need to finish the language school.

But, as it is free, I wouldn`t waste time if I were you. Join it and pass consecutive levels. Then come back and tell us what you learnt.

en.wikipedia.org/wiki/Duolingo

Because the stupid schools - like the one I attended way back - teach about languages, not languages. I spent four years "studying" Russian and couldn't slap a simple sentence together after graduation.

Teachers are the most overrated profession ever. My granddaughters are perfectly fluent in English and can't tell an adjective from a pronoun.

I spent 8 months learning at a school. Polish grammar made me crazy, and all I really learned were the names of things in every day life. Until I got a native speaker teacher I struggled to express myself. I still struggle, but not nearly as much as I did. Native speaker is the way to go. But if you need to take a language test, you will need to know the grammar as well.

Why don`t you start reading the discussion from its beginning? The OP mentioned the modern language school while you are talking about regular high school from 1960s.

I hope that after some thinking you will understand these are two different things.

The native teacher helped you get rid of your psychological barriers in speaking Polish. The same thing may happen in a language school, if you trust and like the lecturer/teacher. Probably it won`t happen doing an online course.