Switching DNS does jack squat for your privacy. Any telecom worth their salt can read all DNS requests no matter which DNS you talk to. They only don’t filter content on alternative DNSes because they don’t care about filtering/blocking in general unless forced to by law.
Using a VPN doesn’t add privacy, it just swapps out who is monitoring your traffic. Many VPN services are actually owned/run by secret services or cooperate with them (like NordVPN). Others are directly run by criminals who use them to steal data or inject malware. Also, VPN providers also have ISPs that reside in countries. In the very best case it’s not your ISP spying on you, but the VPN’s ISP. In the worst case, you now have an ISP and a VPN provider spying on you.
Your own router/modem again does nothing at all for your privacy.
That’s what I mean: people think they are doing privacy enhancing things, but actually what they are doing isn’t helping at all.