I just remembered an old trick that may help. I'm on an older macOS, but there exists
~/Library/PDF Services
and if an alias to an app is placed in the folder, then the alias presents itself as an option in the Print > PDF menu of apps (like Safari). It successfully worked here (10.14 Mojave), opening a PDF of a web page in the app for which I'd added an alias.
Do note the PDF was not yet saved outside of a system temp folder, so if it works on newer OSes then proper saving may be the ideal first step upon PDF creation.
NOTE: I initially specified the incorrect folder (Printing Services) instead of PDF Services.