I turn off autocomplete everywhere I can. Whether web searches, composing code, or anything else, I do not want the computer anticipating what I am about to type. I find it is often wrong, and always distracting.
Yes, I try to learn the language well enough that I know the parameters of common functions. If I don't, I consult the docs. If I need to find the definition of a function in another file, I use grep.
Disclaimer: I do use LSPs extensively, but they do what they are intended to do when I explicitly ask. Offer completions. Format code. Organize imports. All that is available, but only happens when I ask. Same happens where there's no LSP support, and basically the same commands depend on ripgrep, fzf, semantic-grep, external linters and formatters, and plainly compilers.
Me and my tools take turns. It's almost 2025, practically everybody agrees that concurrent mutation of state is a source if trouble.
Similarly, I find in vscode, if I'm writing something on a line based on the line(s) above it, the popups block what I'm trying to look at. It makes sense that you'd mostly be looking at the lines above, not below right? I have to type a few characters, hit esc, type, esc, type, esc. Also, I often have to hit esc before pressing return. Deleting brackets that it added where I didn't want it; I'm probably supposed to highlight the part I want to enclose and then type the opening bracket though; I run into that when I intentionally want to replace some text with one bracket and it encloses it instead. I disabled IntelliSense but I still get the other automatic behaviors. I really like the auto-indent though. That alone makes me put up with the rest, and I'm used to all the ways it gets in the way now. Kind of like how you get used to hitting esc to get out of insert mode in vi.
I'm the same way. I have never, ever been pleasantly surprised by auto completion when I did not explicitly enable it -- can't think of on instance of me doing this, either. In particular, web-based code playgrounds, IDEs, etc. auto-inserting quotes and parentheses drive me mad. Google Docs also frustrates me with their word/phrase suggestion widget that I can't seem to ever fully turn off.
Yes, I try to learn the language well enough that I know the parameters of common functions. If I don't, I consult the docs. If I need to find the definition of a function in another file, I use grep.