Ill get straight into things:

Product I own is Sandisk Extreme Pro 4TB USB 3.2 Gen 2x2 (2000 mbs)

Macbook Pro spec - 2021 M1 Max, 32GB RAM (Thunderbolt 4 ports, 4000 mbs)

Cable - Belkin USB 4 Cable (Box says ‘40GBS’)

Read and write speeds sitting around 850 mbs…? I know this is a good speed, but am I missing something? I understand that the drives 2000 mbs potential is under perfect conditions, but surely I should be getting over 1000 right?