I can give you a bunch of examples of Biden pushing domestic economics and climate change policy real real firmly back towards the center. But, on the broader point about the Democrats in general I actually agree with you. If anything I said sounded like "Let's stop working to make the Democrats better or else find a replacement," it wasn't intentional on my part. Both of those sound like great things to do. (And fixing FPTP to avoid this situation in general in the future)
In the meantime, I do think that voting for the non-apocalypse, and choosing the outcome of "needs some improvement and really should be replaced" over "will definitely try to end the world," are good things to do.
It's like if the neural net runs the life support on the spaceship, and it's clearly not doing a good job and we desperately need to find a better solution, and so one guy says hey it's been so long of this that let's just turn off the life support, what's the worst that could happen.