Yes, the Canon EOS R5 Mark II is compatible with the Sony Tough G 128GB CFexpress Type B.
Sony Tough G 128GB CFexpress Type B is VPG400 class. Meets the floor for: 4K30 (30 MB/s floor); 4K60 (60 MB/s floor); 4K120 (90 MB/s floor). (Peak write 1480 MB/s is not evidence of sustained performance; the VPG400 class rating above decides this.)
“Canon EOS R5 Mark II Compatible Cards: CFexpress Type-B compatible; cards for movie recording should support VPG400 per Canon online manual.”
Last verified:
Compatibility inferred from spec rule (citations above are manufacturer-verified)