Wasn't me, although mine was regularly subjected to 8-9 bar, once even 11 and it was actually a chinese clone of Mini express

Well, you could remove the gauge's pipette from the tee fitting to accurately see what it is pointing to when at atmospheric pressure. If you can get the face off of the gauge you could pluck and then set the pin back on pointing to zero so that the needle is pointing to actual pressures rather than pressures 7.5 bar

I'd always suspect the pump if a vibe pump is more than 7 years old and I wasn't able to test its flow against 10 Bar backpressure. Do you have any way of testing the pressure in the system, like one of those portafilter gauges or anything? (I still suspect the pump, but I'm biased)

I have had the Atom 75 as my first "real" grinder for 3 years. I make about 6 shots of espresso per day with it. If you want to slide the grinder on your countertops, many here have posted on various flat items to put under the grinder, allowing for easy sliding action. Ideally there should be

When it explodes is it overheating or overfilling? (Or... Is the pump running in the moment before the boiler explodes?)