Just an FYI: Borosilicate glass is and has always been very easy to break from physical impact. The og Pyrex was no different. Pyrex changed it to Sodalime glass because modern everyday usage of glass cookware saw much more breakage from slight drops or impacts.

Yes, sodalime is much more sensitive to temperature gradients but we just don’t make many frozen casseroles anymore or really have a need to take a dish from a freezer to an over like they used to.

Neutral is there specifically to handle small surges. Especially in wye configurations and neutral eventually goes to ground. Having it connected to both neutral and ground is a fail safe. No neutral goes to ground, surge too high for neutral goes to both or some large f-up voltage spike from neutral goes to local ground.

MOVs resistance changes inversely to the applied voltage. If the voltage across it increases the resistance decreases and vice versa. They are connected to gnd but have a very high resistance for the normal operating voltage. When the voltage spikes their resistance goes extremely low allowing current to pass effectively creating a short circuit to gnd.