How to turn off iPhone speaker button's other devices option?

How can I stop my iPhone (8 SE iOS 14.6) speaker button from offering other options besides speaker? This is a most persistently annoying feature. I've found various solutions that sometimes seem to work, like turning off bluetooth on my phone as well as on surrounding devices, but the problem always comes back. One Apple help page suggested I turn off “Allow Handoff between this Mac and your iCloud devices.” in the system prefs on my Mac, but my Mac (running OS 10.13.6) does not have that option under system prefs > general.