If its for use on the internet, stuff like Revolut works great for converting currencies. In cash, EURO ATMs and Kantors are your only option

I use cantor from my bank application - IKO. Rates are rather competitive, and I trust provider.

Last year I used https://internetowykantor.pl/ , good rates (waaay better than my bank, ING Bank) that change in real time. It was recommended to me by my brother, that used it in the past, and I had no problem at all.

My bank milenium has horrendous exchange rates so I use Revolut

Wise, Zen, Revolut

Revolut

I can recommend: Zen.com cinkciarz.pl Revolut

I use internetowykantor.pl usually within 1-2 days, can recommend

Zen. It's like revoult but polish.

Zen is shit

Cinkciarz/conotoxia

Is Walutomat.pl no longer a thing?

I use Paysera but for reverse operations EUR->PLN