I sometimes also have the SD card not initialise properly for reasons not always obvious.
It usually doesn’t fail after a cold boot but after a mere reset if fails more often.
However, if your SD fails on first attempt you could retry a few times, maybe with reduced speed.
When that doesn’t help you can try a reset.
When that doesn’t help either then you could opt for RAM based publishQueue as fallback.
But maybe @rickkas7 has some additional suggestions and can also comment on the SD card issue.
BTW, if the sample consistently works and your version consistently doesn’t then you can maybe incorporate your functionality bit by bit into the sample and see if or when it breaks.