In Polish we have 9 such characters and most people use just so called "programmers keyboard layout" which uses left-alt + letter to do the accent.
E.g. alt + e = ę, alt + l = ł (with a one case where we have two different accents for a single letter: z, so we use alt+z = ż and alt+x = ź, the second letter is less commonly used then the first one)
20-30 years ago there were some strange keyboard layouts that didn't use alt, but hopefully they were forgotten.
All typing machines used it, but it was awful for programming obviously, so the "Polish programmer's layout" was added, and because it was exactly the same as standard american QWERTY (except for Left Alt + some letters) it won almost overnight.
Windows still shipped with both layouts enabled for Polish locale for decades, and nobody used the typis one, but there was a shortcut that changed between them.
When you accidentally used that shortcut - if you had Y or Z or Polish letters in your password - you couldn't log in (because you typed "yeti" but got "zeti" but it still looked like * * * * :) )
I think there must have been millions of USD lost on support calls because of that little shortcut :)