My main strategy for dealing with spam is simply having a way of quickly filtering it out based on which account it arrives in.
As far as I can tell, you will get spam eventually. Even if they have to guess email addresses and test which are valid. So I’m far more concerned with how well it can be filtered out than preventing it.
I rarely get any sort of email spam though. They tend to target phone numbers instead, so I’m slowly switching important stuff to a “clean” number.
I personally insist on a dedicated account for financial stuff. Mostly to filter out anything that isn’t explicitly from a bank or insurance.
My “professional” email is just a former personal email address. The only “spam” it gets is LinkedIn updates despite having used it for a few years now to deal with anything professional outside of my actual work.
Using a generated alias for the Job Search itself is something I might consider these days, but some people will view it as unprofessional, since it’s intentionally random. Including myself years back.
I’m less ignorant now, but whichever HR person it passes through first might not be.
A safer option might be using the older variant of aliasing where one account can have multiple linked addresses.
I believe Protonmail premium, Outlook and iCloud all support this. (Not that Outlook is any better for privacy than Gmail).
Alternatively, an account you treat as disposable.