I agree this is infuriating. This was the reason that made me finally ditch autocorrection altogether on my iPhone. I still make mistakes but at least now they're mostly my own mistakes, and when I correct them they stay corrected.
Unfortunately, when I got a Mac laptop, those replacements were synched and for some reason can’t be disabled on just one device.
Now I’m back to autocorrect, fighting with the AI to learn technical terms and command line entries for when I need to talk to colleagues over chat.
Phase 1: iPhone w/o autocorrect but with text replacements.
Phase 2: iPhone and macOS, but text replacements are synched without option to disable. I don’t want autocorrect or replacements while typing on a real keyboard.
Phase 3 (reluctantly): iPhone with autocorrect, macOS without it, and no text replacements.
tl;dr it would be nice if I could disable text replacement on a per-device basis.