Fiscal conservatism doesn't work, any economist can tell you that.
You're completely correct that conservatism destroyed its reputation when it allied with the religious right in an attempt at political power. The regressives took over the GOP, calling themself conservatives all the while. Terrible to watch from the outside, but like I said, giving up is not the answer. The only thing to do is push back, and try to save what can be saved.
I'm curious how you came to your conclusions, too, because the point of conservatism, to me, is to prevent destruction.
I've been a environmental conservationist my whole life. As I became an adult and aware of politics, I came to realize that just as the natural environment requires protection against the selfishness, greed, and short-sightedness of humanity, so too do all the social and political systems that take decades or centuries to build but only years or months to destroy (as we've seen under the current administration).
It's been said many times that at the heart of all conservatism is fear. That's not a very generous way to put it, but neither is it inaccurate. Fear of loss, fear of risk, fear of change. Conservatism holds that if things are pretty good, most changes are likely to make things worse and not better, and so change is to be treated with suspicion, and people pushing for it doubly so, since altruism is rare.
A bicycle needs both pedals and brakes. We need to move forward, but not recklessly. Before a change is made, the case needs to be argued as to why it is necessary, what it will cost (and there's always a cost), how to ensure it actually achieves what it sets out to achieve, and how it might be misused in the future. In other words, before a change can be made in the name of Progress, it needs to be demonstrated that the change actually is Progress. To progressives, this feels like standing in the way of Progress. To a conservative, this is safeguarding Progress, the Progress previous generations achieved, from changes that, again, are more likely to be bad than good.