Okay but even as a native hungarian i have to say “sz” is just insane. Polish is so much more logical with “s” making the non-shushing sound and “sz” making the shushing sound.

Totally agreed. Like, also, everything else that you mentioned, but especially this. I really don't get where they got the idea from, since every (most?) language around has it the other way around, including Latin and German (and their derivatives like romance languages and such). Maybe Turkish and/or Romanian that I can think of, but AFAIK even they put diacritics on their 's' when referring to the 'sh' sound (I don't speak any of those, though, so I might be horribly wrong).
It's especially annoying because most Western European speakers are more used to the Polish sz-s system (which makes more sense), completely butchering words like Szoboszlai (I'm playing E-Football and the commentator pronounces his name like three different wrong ways, about never right).

I had a relatively old teacher ~30 years ago that said 'j' and 'ly' are pronounced slightly differently, giving two examples, and I couldn't hear any difference : ).

I used to go to uni in Szeged so it was quite eye-opening reading about the weird 'e's. So if I got that right, that's the reason they say stuff with 'ö' instead of 'e' in certain cases (because it's not exactly 'ö', but that's the closest regular letter we've got)?

And yeah, 'bicikli' is actually pronounced more like 'bicigli' (or not? Could be regional) and stuff, but what I meant by 'consistent' is that almost always if you see something spelled a certain way you can expect it to sound that certain way, without bullshit silent letters and completely different consonants or vowels. Not in terms of phonemes but actual letters.

And yeah, 'bicikli' is actually pronounced more like 'bicigli'
(I'm still salty about 'bicikli' keeping the 'k' but the short for 'lakodalom' is 'lagzi' and not 'lakzi')

I'd say so. For example, it's common among slavic languages. This one is Hungarian, though. It's right in between, but it's a whole different language family.

Not exactly, a few languages will pronounce them differently, treat them differently for syllable weight, geminate them and even contrast them. A few examples being, in languages that need this que, "ts" is pronounced longer than "c". Syllable weight and syllable structure often treats them as one, with some languages being CV for example where a syllable is always composed of one consonant and one vowel yet they will allow affricates which means they are one consonant(this is alsk the case for prenasalization). In languages that have geminates its often a rule that if theres a geminate in a syllable, its always the coda(so after the vowel) and there can be no other consonant in the coda if its geminate yet it will allow affricates, this is the case for hungarian and sami languages for example from what i know. And lastly in polish for example they even contrast directly with the wikipedia example of "dżem" vs "drzem" where dż is a single retroflex affricate segment and drz is a retroflex d and z after eachother but are not an affricate. They should probably do research on how this looks in your throat and do those sonic analyses they did with prenasalized stops to determine they are actually pronounced differently and arent just quirks in the syllable structure.

True, I might have phrased it wrong. The way we (I?) pronounce that 'c' the tongue position is slightly different from 't' (less of the very tip of it, a tad bit further to the back, close to the tip), hence I thought it deserves the status of a separate sound instead of a transition between the two. Mind you I'm not a linguist and it may be completely bonkers from an actual expert's perspective.

No because in careful speech for example "let's" is pronounced as "l-e-t-s" while in languages that do have the "c" sound, even with careful, slow pronounciation its "l-e-c". English, like every language, has rules about clusters and its basically a rule that "s" always has to be farther away from the syllable nucleus(the vowel basically) than the stop(t in this case). This results in "step" being valid but "tsep" not being valid. Theres also the extra layer of brits being more european so they often pronounce it as "cunami" while americans pronounce it as "sunami" from what i gather. Also another thing is that english doesnt have any base words that distinguish the "c" sound, theyre always loanwords and you can pronounce them as "s"