Can I buy/sell a lot of bitcoins without moving the price? I am curious about how to acquire a lot of bitcoins (or similarly move a lot of bitcoins) without hitting the bid/ask

I don't care about blockexplorer, I am just curious about price discovery

are there any darkpools? could I just use an illiquid exchange and personally contact the counterparty and have them take the trade

options would be good too, this would make acquiring bitcoins at a certain strike easier as this is already a negotiation between the person on the other side of the contract
It won't work, no matter how you do it. If you acquire a lot of Bitcoins, that will mean that a lot of people who wanted to get rid of their Bitcoins no longer want to get rid of their Bitcoins. Thus, they will stop supplying them. The reduction in supply will move the bid/ask prices. It's fundamental economics and you can't change it.