Eth block time and retarget is completely different?
There is no 2 week difficulty adjustment in Bitcoin. It is ever 2016 blocks mined.
3% hash would take 5 hours to mine 1 block. (at 1mb, fees would be astronomical, mempool full, you would not get in, ever, on average)
2016 blocks == 2 weeks with current mining power.
Of course if the hardfork happens just 1 day before the difficulty adjustment, then its a worse.
Plus it only takes 1 big miner to support the fork until the difficulty changes, and then it becomes self sustaining.
Yes in bitcoin it's easier to maintain the majority status quo, but a dissenting fork could still happen.