Greenwebpage is mostly a shared/VPS/eco-hosting company, their reviews are decent for that kind of hosting, but I didn't see any specific track record for Ryzen 9 dedicated servers with NVMe RAID setups. They're based in Europe with locations in Germany, Romania, Holland and the UK.
For a use case as specific as yours (virtualization + dev work, Ryzen 9, 128GB+ RAM, NVMe RAID, remote KVM access).
For best advice - since your workload is virtualization, make sure whichever provider you pick actually supports nested virtualization properly on the Ryzen platform (some hosts restrict this at the hypervisor level), and confirm IPMI/KVM access is included free, not as an add-on. That detail gets buried in a lot of provider docs.