To my knowledge, Blockhashes are determined by the hash of numerous things involving the instruction data of the transactions involved in the block, and the previous hashes.
it is practically impossible to guess the instruction data of all transactions involved in a specific block.
given that, if I set a seed as the hash of a slot greater than
1 minute into the future and
less than 2 minutes 30seconds into the future, then why won't I be able to use the indeterministic nature of these transaction data as a source of randomness.