As a fellow jobseeker, here's some tips for dealing with the scourge of myworkdayjobs:
Use subaddressing to create a "unique" email for each company. My preferred password manager doesn't handle subdomains, so I do myemail+mwd-$COMPANY@provider.com.
The SpeedyApply extension for Chrome, which does autofill for MyWorkDay and other job sites. It's not perfect. In particular, Company Name and Company Location sometimes require a user-initiated edit to be processed correctly.
