Sure, it's possible that "designed to fail" was part of the plan all along.
I think the problem for republicans was in asking conservatives to vote FOR something, like subsidies they don't like, as part of a larger package deal. If they had instead had just floated a bill to repeal all of the taxes on rich people, and do nothing else, I think every single republican would have voted for that. They love to vote against taxes, and they could then blame the democrats for not being able to do more unless the country elects them a GOP supermajority.
They could have claimed victory for overturning part of the ACA, left good health insurance in place for their constituents, preserved their favorite campaign issue for the base, presented a unified win for the cheetoh monster, and appeased their ultra wealthy party backers with billions of $. While simultaneously undermining the ACAs future by turning it into s budget buster.
That's only one of about five different paths I can see that they could have taken, that would have been better for them. I'm still not sure if their avoidance of these better outcomes was deliberate or due to incompetence.