Hi Josh,
When I was test driving the e:Ny1 at my dealership I managed to use a Tesla supercharger at Eurocentral in Scotland when the car first came out October 2023. My e:Ny1 was delivered mid January 2024 and I have heard of no charging issues on the demonstrator.
Setuo the tesla app for non tesla vehicles and it will list supercharges for non tesla.
When i used the Tesla supercharger in October there was only 4 sites available in Scotland, now around 9 sites available in Scotland.