Last time I checked the GCP prices vs. hetzner servers there was a factor of 10 in monthly cost. So I cant say this is a general rule of thumb. It is true though that hetzner can provide superb performance per $. Potentially below what you can do (unless you buy racks of hardware).

Also keep in mind that hetzner is mostly a beowulf cluster. See e.g. this press picture from their newsroom page: https://cdn.hetzner.com/assets/Uploads/IMG-0546-91.jpg

They do have dell servers, too. But don't expect to run on one of these nodes unless the machine type has Dell / PowerEdge in their name. This means the management capabilities are minimal (but usually enough). A fully licensed management card can do way more.

Their renting pricing is ridiculously cheap though. Hardware failure is more common than on cloud providers (see cluster hardware), support has been helpful in the past. Overall IMHO a good choice if you are price sensitive. But even then consider development vs. deployment vs. running (server) costs. Servers might make up less of the total cost of a service than you expect.