NXP KEAZ64 microcontroller fault on power on (harsh/sharp switch on)
That NMI pin is curious but it might just be a symptom of the MCU rebooting over and over.
Some comments:

Nothing in your post addresses low-voltage/brown-out detect, which is strange, as this is the #1 thing to go check. What level have you configured it at and how do you handle it? You have pretty wild contact bounces in the critical area between 2V and 3V. So it is very likely that LVD will kick in at multiple times.

When the part eventually boots, what does it tell you was the reset cause? Power-on reset or something else?

A larger bulk cap on Vin before the LDO is a good thing regardless of if you intend to connect bouncing things there or not.

From the schematic you have provided, we can't tell what goes on with your /reset pin. Do you provide external pull-up or not? What decoupling cap value do you place there and what does NXP recommend? This cap value is often very critical.

Another thing to try is to temporarily tie VADC directly to 5V. In case different parts of the MCU get powered-up at different times, it can also result in LVD kicking in and you might end up in something resembling latch-up. I've had some very subtle problems with this in the past on NXP parts.

How is your SWD connected and do you always have the part powered when programming? Or do you provide power over SWD? This is a common mistake - 5V supplied backwards into your 7805 when there's no input voltage will damage the regulator.