Here's my understanding;
I know some services try to counteract any methods to get past geoblocking etc. with VPN, and that some VPNs offer methods to deal with that too. Presumably DNS services allow further fine tuning.
But I haven't gone into DNS systems so I'm sure there's more to it, and other reasons for its use as well.
This is a very basic summary/crash course.
Most traffic on the internet is encrypted now, so you know source and destination but not what the actual traffic is.
A DNS service basically finds the IP for the domain/hostname name, even though your ISP might see the destination IP there could be multiple domains in use on it(that’s the snooping part).
Normal DNS is not encrypted, secure DNS is.
Using a VPN, all your traffic flows the through VPN provider, so your ISP sees the destination as your VPN IP but not the final destination.
Hence using a VPN but not secure DNS, is often called a DNS leak as your ISP might find out the final destination but not know the actual traffic.
Normally your ISP would handle the transit of your traffic to the destination, so if you’re gaming in Germany and the server is hosted by AWS then at the exchange AWS locally might take care of it based on peering agreements. Using a VPN, your ISP just needs to get it to the VPN provider who then handles getting it to the final destination.
Hence the difference in lag but you’re not going to break the laws of physics here.
Geoblocking really depends on how the service is architected, like I might only need to login from a specific region but then I can consume the service from anywhere. VPNs normally get around this by using a residential ISP IP address in that location as most data centers publish the their IP blocks/ranges, this also means even if the VPN doesn’t keep logs, their hosting service might.
Geoblocking is often combined with payment.
To finally answer the question, I use multiple providers like NextDns, Torguard, Cloudflare Warp, depending on service such as Netflix, Disney+, BBC, Xbox Game Streaming.