The first line, "W Szczebrzeszynie chrząszcz brzmi w trzcinie", has 39 letters. Only eight of them are vowels. If you have any spare vowels, think about donating them to Poland. You'll receive undying gratitude from a consonant-oppressed nation.
It's say it's mostly just Polish orthography. Words look overcrowded with consonants, but it's only because of how we spell them. In speech, I'd say the consonant-vowel ratio in Polish is about the same as in English.
It's similar to why
strength looks like a much longer word than the one-syllable word it is, and
idea looks like a much shorter word than the three-syllable word it is. It's just orthography.
I don't know if it's asking too much (it's a forum about English), but is there a chance you could record yourself reciting
Chrząszcz? It's not the first time you've said you can do it, and now I'm genuinely curious.
Do you have other recommendations for tongue twisters that I could challenge myself with? I've tried
Betty Botter, but my flap t, /
ʌ/, and /
ɑ/ aren't quite there yet.