No. If there is any hope of actual survival, that comes before all else. Accepting the slow death of "voting blue no matter who" means that there is no possibility of averting fascism whatsoever. It is an inevitability that if the only side representing "the left" is associating itself with a declining status quo while refusing to do any of the things necessary to keep that status quo functional, them people will abandon it, and if the only ones offering an alternative are the far-right, then they are the ones who will win. There is no hope of survival whatsoever.

There are, however, two possibilities that do offer some slim hope of surviving. One is that the Democratic party can be pressured into doing the basic, minimal tasks of governance necessary to avert fascism - tasks that they will never simply choose to do of their own volition. The second is that the left can establish a credible alternative outside of the organization of the Democratic party, whether electorally or otherwise. Both of those objectives are furthered by voting third party when the Democrats are offering someone insultingly unacceptable, while "voting blue no matter who" flies directly contrary to both goals.

You're thinking of it as doing chemo when there's no cure. That's not what this is. This is deciding to just take a nice little nap in the comfy snow because your legs are so tired and you'll totally get up again in just a few minutes, rather than choosing to get up and push forward through the darkness in the hope, however slim, of finding an actual shelter.

This "buying time to organize" line is constantly thrown around, I don't buy it as sincere at all, for starters. But regardless, time is not on our side, buying time only means allowing conditions to deteriorate further, it's just procrastinating and kicking the can down the line. And how do you effectively organize an alternative to the status quo and present yourself as separate from it while simultaneously trying to rally around it and supporting it unconditionally? It's nonsense.