is writing ready flash this involved?

I would avoid the EEPROM Emulation completely if all you want to do is save a configuration structure.

Pick one (or two) of the early 16KB sectors (@ 0x08004000, 0x08008000 or 0x0800C000), and then journal the writing of your structure across this space, selecting the last one written, and writing the new/changed one beyond the current.

That's not really "avoiding EEPROM emulation completely". That is, for all practical intents and purposes, EEPROM emulation (although a somewhat coarse one).

I would avoid the EEPROM Emulation completely if all you want to do is save a configuration structure.

Pick one (or two) of the early 16KB sectors (@ 0x08004000, 0x08008000 or 0x0800C000), and then journal the writing of your structure across this space, selecting the last one written, and writing the new/changed one beyond the current.

That's not really "avoiding EEPROM emulation completely". That is, for all practical intents and purposes, EEPROM emulation (although a somewhat coarse one).

It does avoid pretending it is EEPROM and treats it like FLASH, so it does dispense with a rather thick abstraction from ST with an Adddress/Byte storage system that immediately reduces the available space by at least a quarter.

The problem with pretending is that you keep doing things which are inappropriate rather than change the paradigm to a more appropriate one. ie a FLASH within the MPU address space, vs a I2C EEPROM