In my experience, technical people latently believe the thing that people buy from you is a product. So if the product isn't done / ready / etc, then you are being misleading trying to "sell" them or engage with them. It feels wrong, like you're forced to misrepresent yourself.

You imagine the potential buyer as a hyper-critical power-user that will expect everything to be perfect.

But what if the above isn't true at all? What if the potential buyer is buying something more abstract? Like a solution to a problem; or even the chance at future resolution of a painful problem?

And what if they aren't power users? But just need basic help today that could grow into something better tomorrow?

Like, what if they just need a partner to help them solve a painful part of their work, and would be willing to put up with a lot of incomplete stuff to get that?

In that case, reaching out to them to "sell" them in the early days is basically saying "Hey, I'm starting to build XYZ that solves problem ABC. My goal is that it would help by doing DEF. Do you have that problem? I'm early on in the process, and looking for lots of feedback from potential users. Would you be interested in checking out my prototype / designs / thinking on this?"

That doesn't seem "soul-wrenching" or disingenuous or anything like that. It feels very authentic. You're making yourself somewhat vulnerable and portraying yourself as eager to learn and help.

IMO early stage entrepreneurship consists of finding a problem bad enough that non-trivial amount of people say "sure, let's talk" to that pitch and then working with those early users to build something useful.