Had to deal with increasing numbers of spam calls in the last months. So I set up some kind of firewall on my phone.
Found the excellent app SpamBlocker on F-Droid https://f-droid.org/en/packages/spam.blocker/
It has a bit of a learning curve though. With *lots* of options making the UI and UX a bit "special". But there's lots of context help - and it eventually just works.
Next step: actually identify newly incoming spam calls. For this there's a community curated spam list on https://phoneblock.net/
This project has an API that can be plugged into the SpamBlocker app; for identifying and reporting numbers.
Awesome FOSS projects!
