It should be around 25 ms in normal conditions. That's what I got when pinging Hetzner in Germany, from Finland, when the cable was still in use and when using a connection that routes through the cable.
I am don't use Hetzner, but I use ssh between Finland and Germany every day. As a matter of fact even back and forth because of tunneling. After reading the news this morning (Hetzner incident is date 3:30 UTC) I was surpised that I had not noted any lag. It remained very reponsive all day.
I have a persistent VPN tunnel between Finland and Germany and I’ve not noticed really any disruptions. If it had cut out for even a moment, it would’ve interrupted my services (since they don’t recover gracefully at the moment) and I would’ve found out.
I think it is slightly higher than normal. I remember getting 30-40ms pings to germany in recent years. 45-55ms is around the range it used to be in early 2010's before the direct cable from finland to germany was built.
If you want to know if they are affected, search for "Looking glass hetzner". It will help you better than ICMP PING.
See https://bgp.he.net/AS24940 for example.
