Privileged whine and request for advice
Some ideas come to mind:
Part of the problem might be that we view technical problems as requiring technical solutions, when what they need is some short term solution structure and somewhat longer term governance structure.
A roadmap or a strategy is something that you have a structure for adjusting after the first year (or whatever). It doesn't need to be perfect before the organization to start down the path you suggest.
When adjustments inevitably happen, it's not a reflection on your decisions. It just means y'all learned something.
That said, it may help to frame criticism requests as something like "I'd like you five people to each come up with three ways this might go horribly wrong, and suggest how we might mitigate such risks. This will give us a useful starting point to discuss refinements." Rather than the open ended, "Please provide feedback." (the safe space issue is reduced when folks know they are not alone in having to respond, and you get to incorporate risk mitigation activity into your strategic plans.)
(that's probs too much, but I lived that life and have written books about that kind of thing, so I think about it a lot...)