Who would set that?
The proof of work difficulty is set programmatically based on the amount of time the previous blocks took to mine (last 2016). It’s deterministic and cannot be randomly assigned.
Also the block times are ON AVERAGE 10 minutes.
Go over to https://mempool.space and look at the time between any 2 blocks. Some might be seconds apart, others might be 40 min. It all depends on how long it takes miners to find a hash that satisfies the block.
So you kind of have that now.