That was helpful. Thank you. It is now clear that two miners side-by-side would be using completely different inputs.

But what about ALL MINERS in the world? Is the number of different "sig" variations great enough so that each pool changing "sig" in a certain way leads to unique inputs for each miner across the board? I am guessing it is because mempool.space shows ScriptSig to be about 100 bytes in size, of which I am guessing about 90 bytes could be anything, and that's 2**180 - huge number. I guess I answered my own question.

Completely different question... I remember reading something along the lines that a new block cannot be mined 2+ hours ahead of most recent block at the top of the blockchain. What happens when 12 freshly mined blocks are mined faster than in 2 hours? Do miners all over the world stop and wait until some time passes in order not to violate that rule? In other words, what happens to all miners if blocks are mined a little too fast for a few hours?