I feel it'd almost be impossible to find a Clear or Green switches to try out.
That is difficult everywhere.

Cherry MX Green wasn't intended for typing originally but for making the space bar heavier on keyboards that are otherwise populated with Cherry MX Blue. The ones with Greens on the entire board are often special editions...
I have read people claim that WASD Code with MX Clears is a bit loud, but I have not tried the WASD Code myself. The Clear can be a bit more loud than others because it is a bit scratchy.
You will find that people on this forum has greatly varying opinions about keyboard switches.

There is no "programmer switch". I myself have been using MX Browns, MX Clear and Topre at work as a programmer. I have also tried programming with MX Black but didn't like it... while there are others that love it.
I might have been using MX Blues at work if I wasn't afraid of disturbing my coworkers with the noise.
I was about to order WASD v2 with Cherrys Green, but I noticed the shipping costs to Europe would be 60$. That's 30% of the price!
There is also toll and tax on top of the cost of the keyboard and shipping if you import from outside the EU.
You are in luck in that you are used to US-ANSI layout. There are more models in that layout (... and more options if you want to customize it

)
As I understand it there are actually two types of Polish layouts: The US-ANSI keyboard with the use of the Alt key for getting certain letters such as Ł, etc. and an older layout that was once used for Polish-language typewriters and which is used on Polish Macintosh keyboards?
You could also check out computer shops in the Netherlands. They use the US-ANSI layout there also and there should be no added toll for shipping within the EU.
Cherry GMBH in Germany does not only make switches but also their own keyboards. However, most of their own models are mostly a bit dated and bigger and less sturdy than most modern keyboards. I think that
new they often cost too much for the quality they have, but there are often many
used Cherry keyboards for very good prices on German eBay (ebay.de). I have bought several.
German layout is of course the most common, but US-ANSI and other layouts can often be found.
You would need to check the details in the article number though so that you get the right type of switches and other options. There is
guide on the Deskthority Wiki that is quite extensive. The most important info is that the article number starts with "G80" for Cherry MX switches, and then the switch variation is indicated by the second letter after the model number. As always on eBay, be wary of images that are too perfect - those could be stock images and might not reflect the actual item.