When I want to type a special non-English character like Ø, on my Android phone I simply long press on “o” on the keyboard and it brings up every variation of the letter o you could think of.
On Windows, the best you get is “please memorise this giant list of four number codes”. If I’m going to have to google the code I’m probably just going to copy the letter and paste it into whatever I’m writing.
Why not add them to the damn emoji menu (Windows key + .)
It does not. A “native” but unappealing way is to use charmap and/or memorize a bunch of (highly arbitrary) “alt codes”: 0176 while holding alt makes
°, for example. Mostly if you need a bunch of special characters, you use the “appropriate” keyboard or some third-party workaround.