Safari NSURLErrorDomain:-1 Errors?

Has anyone been experiencing frequent “NSURLErrorDomain:-1” errors with Safari 18 and Sequoia 15.0? The error looks like this (I substituted example dot org for a real url in the quote):

Safari Can’t Open the Page
Safari can’t open the page “(https://www.example.org/)”. The error is: “unknown error” (NSURLErrorDomain:-1)

I haven’t noticed a particular pattern yet, but the errors have been occurring frequently enough that Safari is not very useful at the moment. Other browsers, including Firefox, Brave, Edge, Chrome, and Opera, all work fine.

I’ve tried a bunch of purported solutions, including toggling wireless, forgetting networks, clearing caches, closing all tabs, rebooting, making sure iCloud Private Relay is off, etc.

Solutions and/or sympathy welcome!