Hard crash - purple screen

If a clean install was performed and the "Descript" app is the only third party app installed and it does not contain a driver, then you have a hardware issue with the Mac --- most likely a bad Logic Board, but you can never rule out a power issue. Apple does not train their service techs to understand Kernel Panics so Apple will usually blame the third party software even if it does not contain a driver. See if you can get the laptop to Kernel Panic with just the original Apple apps instead of installing any third party apps. When a clean install of macOS crashes with no third party apps installed, then the Apple techs will take notice and look for hardware issues. However, even then it is best if you can get the laptop to crash regularly with the original Apple apps so that the repair tech can verify the failure and to hopefully verify the replacement part was the correct one, otherwise it is anyone's guess whether the correct part was replaced unless the diagnostics report a specific hardware issue.

Good luck.

Diagnostics are really only useful when they detect a problem. Just because a diagnostic passes does not mean the hardware is healthy. Usually Apple only performs the quick MRI test which is a joke of a test as it only does a quick test of the memory and checks the sensors. Apple's other more detailed diagnostics should be run, but they take time and even then they usually won't detect some problems.

The clean install is the best test especially if the computer fails without any third party apps installed. When testing with a third party app it is best to be careful to use one that is known to be stable and compatible and which does not install any drivers so if the computer Kernel Panics you know that it is due to a hardware issue. An app that does not contain a driver should not be able to cause a Kernel Panic so I think it is fairly safe to say your laptop has a hardware issue.

panic(cpu 9 caller ...): "FED err (L1C I-side data parity)

on P-core: FAR=0xda FED_ERR_STS=...

MMU_ERR_STS=0 ErrDet_Addr: VA=0x18304b400" @AppleFireStormErrorHandler.cpp:599

Data Parity is used in places like Level-1 caches [suggested by L1-C I-side] where dropping or adding bits would be a disaster, but nearly undiagnosable. Simply stated, it is a Hardware setting of a number of bits across one word, such as to an odd number. It requires at least one extra check bit be added all the way through the device and the busses. It is set in Hardware, carried by hardware, and checked in Hardware. This checking is done on-the-fly in Hardware. No 'ordinary' software you add can change these settings or checking.

For odd parity: If you 'add up' the number of one-bits across a word, and the result is odd (odd parity), then there has likely been no corruption. If you 'add up' the number of one-bits across a word, and the result is even, one bit or possibly more have been clobbered.

Executive summary:

You have a serious Hardware problem in your Mac, probably related to the processors and or their hardware caches. It likely needs its motherboard changed out for a good one.

Your mission is to make a case that is so straightforward, that the failure occurs repeatably in all-Apple software. Then replacing the mainboard can be shown to solve the problem.

You MUST have a Trusted backup to proceed.

The way to get this resolved to get Engineers' eyes on your crash report.

That is available to polite-but-persistent callers on Apple telephone support line, once they have you 'jump through the prescribed hoops' and not solved your problem, they are supposed to escalate your issue to a specialist.

A specialist will be far less patient, but may have training in reading your crash report, or be able to file a bug report with an Engineering team that can read it.

Apple phone support does not take the word of posters here, but the panic logs already posted can be referenced by passing a link to your postings here.

That is just the "app Apple software" kind of report they will start to pay attention to.

All the reports you have posted are Input-side parity errors on a performance core. it won't occur at idle, but once you start using the performance cores it will rear its ugly head.

You can suggest that to them, but as I said, they have no particular respect for opinions from Users here.