Got a term sheet with 2x participating preferred. Walk or sign?

Small round, our first priced. The lead wants 2x participating preferred. I've read enough to know participating is unusual at our stage and 2x is aggressive.

But this is our only term sheet. We've been at it for 7 months. Cash is short. I keep telling myself "fix it in the next round" but I know what fix-it-in-the-next-round usually means.

The investor is well-known and would be a real signal. The terms would make the next round much harder and any exit below $40M would mean the team gets nothing.

Is there a clean way to negotiate this down, or do I have to be willing to walk?