You'll get no argument from me with regard to the typing plus autocomplete crosstalk going on being distracting. Hence the reason when I know that someone wants as close to silence (you probably do want words to be announced as you complete them) as you can get and a search is complex to formulate your search criteria either in a text editor or word processor, then copy and paste.
Everyone has their own preferences, which is fine, but when it comes to turning off autocomplete that has certain ramifications that may not have been considered. Sometimes using workarounds turns out to be preferable, sometimes not. Just laying out some options, as are you.
Brian - Windows 10 Pro, 64-Bit, Version 1909, Build 18363
Tolerance is the positive and cordial effort to understand another's beliefs, practices, and habits without necessarily sharing or accepting them.
~ Joshua Liebman