Will gopro8 crash with 256g memory card?

I won't. Gopro8 can support up to 256G memory cards, and a few brand models can support up to 512g (Lexar1066xuhs-1silver series–512gb). GoPro official package recommends two capacities: 64G and 128G.

Expansion: The gopro host itself does not contain storage space, so it is impossible to shoot without a memory card, and a qualified memory card must be used. Gopro requires that the memory card must be a TF micro-SD card above U3 level, that is, the writing speed must be greater than 30MB/s to meet the storage requirements of 4k video.