Yes, the Canon EOS R8 is compatible with the Delkin Devices PRIME SD V60 128GB.
Delkin Devices PRIME SD V60 128GB is V60 class. Meets the floor for: 4K30 (30 MB/s floor); 4K60 (60 MB/s floor). (Peak write 105 MB/s is not evidence of sustained performance; the V60 class rating above decides this.)
“Canon EOS R8 Compatible Cards: SD/SDHC/SDXC with UHS-II and UHS-I supported; for movies use a card with ample performance (fast enough writing and reading speeds) per Canon online manual.”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)