If postwar Ukraine has limited sovereignty, there might be no point, what will be left to do is waiting for Russia to finish the job. I highly doubt that Western companies come and seriously invest without guarantess for Ukraine's security either.
If there's any 'betrayal' here it's not in helping them against existential threat in the first place. It's not doing enough to help them win (I count the survival of independent and sovereign Ukraine as a win, even if it ends up smaller). That it would be a betrayal of ourselves as well is another thing, we'd pay for it too, with interest. Ukraine with limited sovereignty is what I count as a loss, that one will probably spark another exodus of the Ukrainians, I believe we should allow them in that case (they're not some dysfunctional third world rabble, so no problem here either). Pour money into a country that will only exist on Russian goodwill, until they decide to go in again? Nah, that would be sheer stupidity.