The safety requirements for charging in Europe are not the same as the US for several reasons. One difference as I understand it is that the European "charging box" (the EVSE in the US) cuts off after a single ground fault detection. In the US, a few retries are allowed for about 15 minutes, I don't recall exactly. Also, the leakage current threshold is lower in Europe, as the voltages are higher. Nothing in the US is more than 120 volts with respect to ground in residential areas. I recall the fault threshold is about 0.02 amps in the US, and 0.003 amps in Europe, someone please correct if I am wrong.
The three-phase portable charging box (UMC in Tesla terms) is quite a challenge in Europe, I am not surprised Tesla has delayed shipment. In my view the issue is that the standards document (IEC 62752) is not mature yet. It is theoretically understandable to require detection and protection against every possible type of mis-wired outlet, but in practice it is perhaps not workable and some of the provisions (like switched protective earth) might actually not be allowed in the US, as it is arguably more dangerous than what they are trying to protect against in some situations.
If it is any comfort, the BMW Mini E was notoriously unreliable when it came to charging if your supply voltage was on the high side of the range, which typically happened in winter. I used to turn on every electrical device in the house to get the voltage low enough to start charging the car. It was a very nice change when we switched to the Norwegian designed Think City EV, which pretty much always charges. Perhaps if it will charge in Norway, it will charge anywhere.
I would not pay much attention to comparisons with Japanese EVs. I have seen some Japanese plug-in cars that will charge regardless of no protective earth connection at all (called safety ground in the US). It is easy to increase mission readiness by compromising safety.
And yes, I also recommend visiting Rjukan. I saw it back when the hydro plant was still producing. But this time of year I would stop in Telemark and go cross-country skiing. Telemark has the autobahn of cross country ski trails.