If you’re reading, the capitals are different, so that’s 52 letters. In the real world you may encounter cursive, so that’s 52 more letters.

So to read English, you’re looking at 104 distinct characters, and that’s before you discuss diphthongs and digraphs.

eh, I don't know. Cursive is pretty rare nowadays. You also in my opinion do not really need the capital letters, and many of them look like their lowercase counterparts, but I take your point. I definitely think English can be tricky to learn, though, and feel lucky to speak it natively given that it is the lingua franca in many (perhaps most) contexts.

I don't think letters being in cursive is semantically important. Letter case is, somewhat.

I think Cyrillic doesn't even have letter-case, which I've often found interesting.

But it does. Most of the lower case letters are simply very similar to the larger upper case ones. Upper case, or majuscule, is used as the initial letter of a sentence and for proper nouns just as in English. At least that's what Wikipedia says.

See: https://en.wikipedia.org/wiki/Cyrillic_alphabets, https://en.wikipedia.org/wiki/Cyrillic_alphabets, https://learnrussianstepbystep.com/en/capitalization-in-russ..., etc.

There is some common base though.

E.g.: If you’ve seen the letter “o” in one variant, you’ve seen it in other variants too.