I agree it shouldn't be needed, the issue is that I get a bunch of job ads that outright say "provide a link to your portfolio". Which seems to assume that every applicant has a website with info about their work or something.

IMO, just leave it blank and highlight your work experience. They're hiring you to develop at work, not develop at home. Recruiters ask for lots of stuff that isn't necessary.

Again, I'll highlight that I've worked with tons of developers, designers, and PMs and almost none of them had portfolios.

FWIW, I've just fill in "N/A" or shared a Google Drive link to a PDF if required.

I've gotten all my jobs despite not having a website.

The downside, of course, is I don't know how many jobs I MIGHT'VE gotten if I also had a fancy, polished website. Shrug. I don't really lose sleep over it at night. Of all the devs I've ever worked with, none ever had a portfolio.

(The designers usually did, of course.)

I'd just substitute your GitHub profile assuming you have one, though I will say that "portfolio" does seem to imply a UI/UX position.