Is the cybertruck a commercial or a passenger vehicle? If tesla want to reclassify it as a commercial vehicle then they can do the conformity testing under those regulations, and then it will be subject to all the other rules such as class of license needed to drive it, having a tacho, having a speed limiter etc. If they want to sell it as a passenger vehicle then it needs to comply with those regulations - which, by the way, are still the same as the EU ones, so this isn't a UK-only issue.