You don't need to use alt codes.

ãâäåáà, êëéè, îïíì, õôöòø, ûüúù, æ, þð, ñ, ýÿ, ç

Behold, you can type all these and probably a few more by just combining two keys or in some cases three (a little more annoying than capitalizing) and using the English United States International Keyboard layout on a Microsoft keyboard... And how do you think French people write in French? They have to procure diacritics as well. The input is basically the same as how I do it, except their physical keyboards also have the markings on them so you don't need to memorize it all in your head.

https://www.starr.net/is/type/intlchart.html

Literally all Microsoft has to do is extend this keyboard layout and it would be able to handle more languages.

edit: why is this a video lmao

Also it's already bad enough figuring out a Chinese word with just the pinyin. If you're not even given tones then there could be dozens of meanings.