Geschlecht europäischer Ländernamen in polnischer Sprache

Q: What is going on with the Netherlands, Austria and Italy?
A: I included alternative names of these countries, and those names have different gender.

Italy – Włochy (Plural, official) and Italia (Feminine, much less common)
Netherlands – Holandia (Feminine, unofficial) and Niderlandy (Plural, official, but much less common)
Austria – Austria (Feminine, official) and Rakusy (Plural, used very rarely, mostly in regional dialects or in old historical texts).

Almost same as in Russian except only plural are Netherlands, all other plural are female in Russian. And Algeria and Tunisia are male in Russia (Алжир, Тунис).

why do countries have genders? 🧐

How does ‘plural’ work? As in ‘(the) Germans’?

as a Turkish, i never get to understand why these people have genders in their languages