Whenever we interview a candidate, the one thing we give high premium on is structure, the rest come next.

bad variable names, long complex code...can easily be adjusted. If the candidate doesn't have a good understanding of how to structure a code (what goes where, for what purpose, separation on concern...), it'll take much more effort to teach that candidate than to teach the bad variable namer.

Properly structured code naturally leads to a better performing software, even if/when a bug arises it'll be easier to spot / test.

All that being said, if a coder names a variables, 'a', 'aa', 'aaa', 'aaaa' that's a serious red flag.