Max-Zorin
Please bear in mind that using a custom DNS will not prevent your ISP from monitoring the traffic as they will still see the domains you visit. If you want to hide from ISP then you need a VPN.
As for DNS, any of these will do it: https://www.privacyguides.org/dns/
They are also public which means thousands of people are using these so you won't be unique.
My personal favourites are:
Mullvad with adblocking (adblock.doh.mullvad.net)
Adguard (dns.adguard-dns.com)
You might also be interested in Adguard Private DNS which allows you to customise the filters. Its free for 300k hosts per month (overkill for me) and is also resolving to public Adguard DNS so your DNS won't be unique for fingerprinting.