I think you are misunderstanding what I say and are criticizing that.
Earlier you said 'record the contract' even though purchase contracts don't get recorded. I knew what you were getting at and did not accuse you of misinformation.
You say a lis pendens is a lawsuit, but that's not true either. Is that misinformation?
Yes a lis pendens signals a lawsuit, and a lawsuit must be filed to record a lis pendens. However filing one is cheap and does not require the cost and time that executing the lawsuit would. But title is still clouded which creates the leverage the OP is after.
Even if it is not recorded, the OP could say to the seller, "Work this out with me or I will cloud title" and that can create the same leverage.
It depends on the specifics and I'm sure a lawyer could point out some technical inaccuracies in what all of us have said, but I believe this is a legitimate avenue to explore to address OPs goals.