My last post was a bit verbose. For solving the task (populate a long a** json array/string with 5-40k bytes) I had 3 options :
- use the RAM, but I was at 85% capacity quickly (32kbyte, but this was on MKR GSM 1400)
- use the Flash (via FlashStorage.h), but I would write way too often and quickly wear out the cells
- use SD, will also be worn out but not as quickly as the small Flash
I went for the last and slowest option.