If you continue getting Kernel Panics, then please post several of the Kernel Panic log files here so we may get more information from them to see if the Kernel Panics are of the same type or different. Kernel Panic logs are located at "/Library/Logs/DiagnosticReports" & sometimes in the "Retired" subfolder usually with "kernel" and/or "panic" in the file name. You would need to post them here using the "Additional Text" icon which looks like a piece of paper on the forum editing toolbar.
The EtreCheck only shows a single Kernel Panic at the time of the report which appears related to "FindMy" and may be a general protection fault which could be due to a memory issue, or bad software. Your EtreCheck report doesn't contain the usual culprits, so I would be leaning towards a hardware memory issue.
A memory issue could be caused by a lot of things.....bad or incompatible memory, CPU issue since the Intel CPU contains the memory controller, the Logic Board, or power issue. Generally third party memory will be the problem....either a bad memory module, or the memory is incompatible with the Apple OEM memory and/or the computer itself. Macs are very picky about they memory they use. In my own personal experience supporting my organization's Macs for decades.....the Apple OEM memory modules rarely fail.
Unfortunately it is very difficult to test the memory in the more recent Intel Macs. The Apple Diagnostics are unlikely to find memory errors (even the service diagnostics) since they only run very short & limited memory tests.
Unfortunately the bootable MemTest86 USB stick is of very limited use for a 2019 iMac, but it is about the only real option.....just do not modify any of the MemTest86's test settings or the test will most likely freeze up. You can use the downloaded MemTest86 .img file as a source for Etcher (Mac, Windows, Linux) to make a bootable MemTest86 USB stick. You will need to Option Boot the iMac by holding down the Option key immediately after hearing the startup chime. Select the orange icon with "EFI" to boot the MemTest86 USB stick.
If MemTest86 shows a memory error, then it likely indicates a memory is bad. If the test freezes up even with the default MemTest86 settings, then it may indicate bad memory. You can remove a memory stick & try MemTest86 again. Rinse & repeat. If you find the memory test runs fine after a previous failure, then the removed memory stick may be bad....or possibly just incompatible.
If the test provides an error or freezes up, then I would start by removing one of the third party memory modules. If it still fails/freezes, then remove the other third party module. Still a problem, then delete one of the Apple modules.
If one of the third party modules is causing the problem, then try that module all by itself to confirm if it still fails. If it works by itself, then try adding the other third party module. If it now fails, then it indicates a compatibility issue with the third party modules.
It is possible MemTest86 won't provide any answers, but it is your best option to identifying a memory problem assuming it is caused by one of the memory modules. The trick is to find a quickly repeatable method to show a problem so that you can test each memory module relatively easily. This is how I have been able to locate bad RAM on Macs for years (at least with older Intel Macs I could modify the MemTest86 settings to have more options....not an option for the 2019 iMac).
FYI, it is extremely rare for more than one memory module to fail at the same time.
