In France, thanks to STIR/SHAKEN, this is not possible any more for the fixed phone numbering plans (and telemarketers have to register their phone numbers in a subset of this numbering plan). For mobile lines, this is still not 100% implemented due to the difficulty of handling roaming, but I think it is becoming efficient as I didn't have a telemarketer with a mobile number since a long time (they seem to hide their number now).

Not in the domain at all but wasn't this the purpose of STIR/SHAKEN but the biggest blocker was that large telcos hadn't deployed it? I think Android and iOS dialer app show you whether there was Caller ID Verification done or not so you may be able to drop anything unverified.