That’s in direct conflict with how LoRaWAN is designed to work - the entire concept of LoRaWAN from the LoRa Alliance and so applied across the entire industry is that it is a network which carries state forward. Cold restarts aren’t supposed to happen.
That wouldn’t be enough, anyway - you also have to save the uplink and downlink frame counters, channel map, RX2 settings, ADR state, giveup counters, and probably more I’m not thinking of at the moment - really all state… Do so constantly and you potentially wear out the EEPROM in the long run.
Really, LoRaWAN is designed to be implemented on nodes that either retain state in RAM by using a low power sleep mode (as it was already mentioned this module does), or use some novel non-volatile storage like a magnetic RAM.
Given your intended quantity, you really, really need to do this right. Doing an improper rejoin every time you power up will cause no end of trouble, it’s also extremely wasteful of battery as you exhange several unnecessary radio messages. Plus since you can only join with a unique not previously used join nonce, you’ll start seeing the join requests themselves increasingly ignored.