How do I identify and remove this spammy malware "Suggestion" app?
It turns out to be &quot;Bluetooth Auto Connect&quot; that introduced this spamware-like behavior. This app had been installed for a long time but apparently only recently changed its behavior. I will find a replacement.
Thanks to a tip from @Firelord, I was able to determine the actual app (process?) by:

Pressing the main Android square recent / running apps button

Long-pressing the title bar of the &quot;Suggestions&quot; window.

Pressing the (i) icon which shows up after the long-press. This showed the actual app name.