Had a similar struggle with the German layout, but in the meantime I have moved to the “EURKey” layout. It is built in to many distros and available for Windows and Mac. It mimics a US layout while still having all the äüöß (and much more) I could ever need. Though I will say it’s only really worth it if you’re in IT or similar where you frequently need certain symbols.

: as a directory limiter is crazy 😅
(Never been an apple person)
Good to know that NT also supports / though. Somehow it never occured to me to try.

Only time I’ve ever used \ in a non computer context was in mathematics as “without” in set theory. As an escape character it’s pretty practical too :)