Congratulations on the PhD and welcome to industry! This is your introduction to the bizarre hazing ritual we've had going for decades. Many many companies use the algo/ds knowledge filter as proxy for IQ test.

You get to decide between a) drilling leetcode for a couple of months, at which time you know the shibboleth and whisper it at large swaths of companies to gain admittance; or b) look for companies that go with a more liberal but likely still uncomfortable interview ritual.