Is Factory Reset forced when using ODIN to revert back to previous UI 2.x?

[Dual-eSIM-S24Ultra]

When using ODIN to revert back to a previous Android and UI ( ie. A10 and UI 2.5), and once the respective Samsung files have been successfully flashed to the device,  is there anyway to avoid Factory Reset?

Or is the factory reset a required step? 

[RedDogRabbit]

This post is a load of utter nonsense! 

Samsung's Firmware IS & HAS been available online for at LEAST a DECADE!! 

Sammobile.com

SamFirm

XDA

Frija

How can a Samsung Moderator be so poorly informed & post a completely  FALSE statement!!!!

[RobertZ]

Flashing new firmware will reset the device.