When you have 20 years of experience, you probably don't blindly submit resumes for listings anymore unless you have zero connections at the company you're applying to.

And connections can really just be "anyone who can get you an e-mail address of a hiring manager"

Personally my approach is to treat the cover letter upload like an introduction email and not bother with all of the traditional cover letter stuff. Keep it simple like

"Hi, hope you're doing good, I'm this person with X years of experience, I like what you do and I want to be a part of it."