Hi @vlamingBoyz,
Good question. I don’t have a single solution to your answer but similar questions have been ansked before so searching the forum with the search option may provide you some more information.
IIRC someone made an implementation of this for ESP32 (which loses state when it goes to sleep). That might serve as an example (I have no link for it).
See e.g.: What LMIC state must be preserved during sleep mode?
Instead of adding EEPROM it is also possible to add FRAM (i2c would be the simplest from hardware perspective and SPI would be faster, but not an issue for this type of applications)…
Lifetime of FRAM and the max number of rewrite cycles for the memory are practically limitless, it’s fast, write speed is as high as read speed and IIRC uses less power.
The disadvantage is that available memory sizes are smaller (but sufficiently large for storing LMIC state and more) and they are a bit more expensive.