IP NetworX was one of the most popular PBN hosts in 2015, however, their reputation has been rapidly going downhill since then.
Even though they state the lack of footprints, with even a basic 10-blog setup you can see the failures of the setup. The majority of the IPs they provide are assigned for “gaming” (think gaming servers), not “hosting”. Why do they use them? Because they are cheap, easily available and simple to buy. They say they only provide nameservers on .de domains (which would be bad enough), however, that is untrue because all of their nameservers are custom and only their users use them. There is absolutely no worse footprint than a custom nameserver!
They don’t disclose the hosting providers they use. That is because they use only one – French OVH. How do we know? Because when in 2016 OVH provider went offline for hours, all IPX blogs went down with it.
The setup of IPX is pretty standard for a pre-2010 SEO host: VPS servers, bought IPs, custom nameservers. There is nothing they do differently and it’s why SEO hosts got deindexed in the first place.