I've always wanted to learn Loglan/Lojban because of that, but those are even more niche.
For example: Right alt + c = ĉ
For linux its pretty simple, you just have to use: setxkbmap -layout us -variant altgr-intl -option esperanto:qwerty
Spanish is surprisingly close to "one letter one sound" for being an organic language. If you see "papa" and "papá", and know the rules of syllabic stress, you can pronounce them without ambiguity. And it only uses acute diacritics on vowels, and the letter "ñ".
I acknowledge that I'm probably biased towards Spanish because it's my native language. And honestly, languages heavy on diacritics, like Vietnamese, spook me.
[0] https://apps.apple.com/us/app/esperanta-klavaro/id957192189
Ĥ/ĥ is less common in esperanto and in some cases has been replaced with other letters.
To me it's not that weird once you learn it.
I think the only word I wasn't able to understand was "hejmpaĝo", which I guessed to mean something like "especially"
Could google it, but finding it out by guessing and asking someone seems more interesting.
It means homepage (constructed from hejmo = home, and pago = page)
I give a lot of credit to whoever put together the Duolingo course, there's a lot of amusing innuendo with Adamo kaj Sofia and apt sentences like "Li trinkas bieron, cxar li estas malfelicxa".