Formatting of iMac 2019 HDD and Disk Utility Persistent Error: (69716)

Dear All - Here is the question in a nutshell, as best as I am able.

If a Fusion drive was formatted outside its 2019 iMac enclosure, being connected to another computer (with another User operating it) and an upgraded OS installed from that computer or drive attached to it, (i.e. no communication with Apple servers for the OS), could there be a problem for the operation of the Fusion drive once back in its rightful enclosure?

As a total amateur, I am wondering if the SSD part of the Fusion drive, being physically separate from the spinning disk HD when these big changes were made to it, could be responsible for a persistent Error I am getting from Disk Utility, namely "Storage system verify or repair failed: - (69716)".

This message is important because it appears in both normal and Recovery modes, when using First Aid for the Macintosh HD with its Data volume, or at the higher up level of Container. I have numerous First Aid reports, all saying the same thing about the "volume /dev/rdisk2s1", giving the message at the end of its scan: "The volume /dev/rdisk2s1 with UUID 31F87150-5459-4ABE-A09F-A08B23C75124 was found to be corrupt and cannot be repaired."

Additionally, the message "Storage system verify or repair failed. : (-69716)" was presented when I tried to Reinstall OS Sonoma from inside Recovery (to see if this cleared the 69716 storage system problem). And when I tried to upgrade to OS Sequoia via System Settings, that also failed. It could not be installed.

I am advised by Apple Support to try erasing the HDD and then see if Reinstalling OS Sonoma can work normally, i.e., the error has been cleared by the erasing procedure.

BUT, as I am so dependent on this computer, which is working FINE except for the problems noted, I am very apprehensive to do a testing procedure by erasing the drive only to find that reinstallation of Sonoma still fails and then the verdict will be 100% clear - I have to either buy a new internal or external HD/Startup Drive which will have to be an SSD. This outcome would then leave me without the computer for many days on end as I attempt to sort out a replacement for the Fusion drive. I dread that being the consequence of erasing the drive! And it is not cheap, even in Mexico, to get someone to open this iMac up.

In my amateur way, I am wondering if the physical, and therefore electronic, separation of the two components of the Fusion Drive at the time of Erasing, could have messed up the storage drive. But maybe this is not a relevant variable! Does anyone know how the 2019 iMac might respond?

BTW - Three softwares have checked the physical performance of the Seagate drive inside my iMac and they have not come back with any dire message to replace the drive. I used Etrecheck, DriveDX, and the technician used his Crystal Disk Info software, (perhaps through running Windows on his Mac, or on a Windows machine, I have yet to get confirmation of exactly what his process was).

For anyone suggesting I take it in to an Apple Store - both logistics and cost issues come into play, and of these cost issues are significant, in order to cover the logistics costs! If I can reach a reasonable estimation of how it is that the Fusion drive has got some 'corruption' on it which is causing problems, I can at least plan the various expenses ahead of time.

Big thanks in advance for comments that might help me make my decision about the next step with more confidence. :-)