It is possible and there's IDE extensions for this at minimum for VSCode, it's just impossible to be consistent with tab indents, because you'll inevitably have to align with a space.

> it's just impossible to be consistent with tab indents, because you'll inevitably have to align with a space.

That's definitely application specific. I've seen other applications (not IDEs) use variable width tabs so that tabular data (Tables) would line up very well with only a single tab.

Because if someone sends me 8 space code and I'm normally 2 space code rendered as 4 spaces...

And if they send you a 8 tab'd code and you normally only use 2 tab's then you'd have an issue as well.

Then your editor renders the 8 space code as 4 spaces without missing a beat. Why wouldn't it? Detecting the indentation level used is trivial. (Provided, of course, that the author had the foresight to use spaces, not tabs.)

>Detecting the indentation level used is trivial.

I agree that parsing a known correct file is trivial. Wouldn't a trivial thing be solved by now?

Whenever I open a C file in Emacs, the indentation level is autodetected. I'll admit that may not have been trivial to implement, but it certainly has been done.