Is this a correct statement? There is ABSOLUTELY NO POSSIBL…

Lets say there was a billion dollar bet riding on block 700000 having a last digit of 0... And you were a miner with massive hashpower, you make the bet, after 699999, you mine blocks at a ridiculous rate, and publish the one ending in 0

*secretly mine blocks ... This is the only way I can think of to predetermine what the last digit of the block hash would be. Am I correct in this line of thinking?

It's a question of economic feasibility. I don't know why you are asking but it would be a question of is it profitable. If this is for some kind of gambling, you would set a max bet in line accordingly.

For example, if there was a reward that was more than 16x the block reward I would receive as a miner, it would be profitable for me in the long run to attempt to find another block that has the desired ending.

Right, cheers for the answer, I was basically just trying to confirm that there was no special maths to guess the block hash ahead of time - thinking of using the last digit or digits of a certain block hash in the future for provable RNG for a system

If you don't want the miner to be able to have influence. Each block pick a salt value, and publish a hash of that salt to the chain so it's included in block. Then the seed for your RNG is (salt + blockhash). Miner won't know salt so cant influence outcom

But since you published the hash of the salt to the chain to be included into that block. After RNG event is done, you publish the salt for that round. People can hash the salt and verify it matches, as well as use the salt+block seed to verify rng outcome

Right right, yep that makes sense