You should be able to do it from the native Google phone app - in the settings there’s a menu for blocking numbers

Check out Silence. I find it works great. It doesn’t contact any external domains when running in the background; runs entirely locally so it can work on Stock Android or GrapheneOS. Inspected it via VirusTotal before installing it, and is clean. You can set it up to block all contacts except for those on your contact lists. It comes with other options as well, depending on your preferences.

I use a dialer called ACR Phone.

It does automatic call recording (poorly, like every other app that’s on a non-root phone, but I digress) and caller ID based blocking. It also supports SIP accounts and other really useful stuff for me.