What app is out there for my phone to block spam

Right, there is no need to block them when you have Silence Unknown Callers on.

Blocking numbers isn't very useful even if you don't have Silence Unknown Callers on as many scam and marketing calls spoof the number that they use and change them constantly using new numbers.

It wouldn't have made things worse but wouldn't have made it any better either.

It does seem to me that the number of attempted spam calls I get has gone down over time since I have had Silence Unknown Callers on but no way to prove that.

I open the phone app and tap Recents at the bottom of the screen and then tap Contacts every day or so just to clear the notification number for the Missed calls.

One option that works perfectly for me is Settings > Phone > Silence Unknown Callers. Also see: Detect and block spam phone calls - Apple Support

With Silence Unknown Callers turned on, there is no need to manually block calls.

Open the Settings app,

scroll down to "Phone"

check that the switch beside Silence Unknown Callers is green.

I don't look at them. They will be listed in Recents but that doesn't cause any issue for me.