https://f-droid.org/en/packages/org.fossify.phone/
Then in the options you can go in "manage blocked numbers".
Then you can activate "block calls from numbers not in contacts".
I don't recommend to filter number by number as domestic proxies gives virtually unlimited amount of numbers, but know you can import export those list if needed.
Right now I'm looking if there is a free/libre android software that does Call Screening, meaning that not only calls not in your contacts are blocked, but instead of a hard block they have to leave a voicemail and you can know if it's legit or not and you choose to call back if needed.
