It depends on where you live. In Germany, forced arbitration in general TOS is invalid and has to be separately negotiated and agreed to. In general, what you can put into your TOS is pretty restricted, anything you put in there that a consumer wouldn’t reasonably expect is not gonna be legally binding.
Not really. Timezones, at their core (so without DST or any other special rules), are just a constant offset that you can very easily translate back and forth between, that’s trivial as long as you remember to do it. Having lots of them doesn’t really make anything harder, as long as you can look them up somewhere. DST, leap seconds, etc., make shit complicated, because they bend, break, or overlap a single timeline to the point where suddenly you have points in time that happen twice, or that never happen, or where time runs faster or slower for a bit. That is incredibly hard to deal with consistently, much more so that just switching a simple offset you’re operating within.