Today, I use an iPhone and now use voicemail as a basic call filter. If I get a call from a number I don't recognize I immediately let it go to voicemail. At my leisure later in the day I can check the transcription service to see if it's spam.
I find it bizarre that the feature fell out of use for me, and came back into it because of this recent spate of spam phone calls.
It's not on F-Droid, but the source code is available on GitHub.
Play Store listing: https://play.google.com/store/apps/details?id=com.jachness.b...
GitHub repo: https://github.com/jachness/blockcalls
I really wish they'd just make some kind of system or authority to keep VOIP from spoofing numbers. It's ridiculous. There's gotta be a way for them to secure that shit. I guess they're just inept.