They do have built in DNS protection, it’s just not DNS servers controlled by them. You can pick presets from AdGuard, Cloudflare, etc. Or, use your own.
Regarding logging, I’m not sure I understand entirely how it’s relevant to a service such as SPN. Have you used Tor and wondered if the nodes are logging? SPN is also an onion router. So, the exit node will not know your origin, even if they are logging. Of course, we could go down rabbit holes about speculative traffic correlation and/or timing attacks, but that’s a separate discussion. A large portion of the SPN network is also community operated nodes.
SPN nodes can also be run by anyone without needing a large investment of staked cryptocurrency, unlike another onion router Lokinet. This lowers the barrier to entry for a more diverse number of community contributed nodes to SPN.
These aren’t necessarily multiple VPN connections. Instead, every network request is sprayed across the SPN network based upon your desired number of hops and other settings. This means one app might see you as being in Iceland while another in Australia, etc. It bounces every connection around the network. If someone were trying to track you, it’d make it just a little more difficult than a static location connection with a traditional VPN.