A decision record can't answer everything.
I don't think it should either. I can't imagine anticipating every question anyway and trying to do so would turn a useful explanation into yet another document nobody has time to read.
What if someone finds the record, understands the reasoning and is still unsure whether it fits their situation? It's bound to happen.
That's okay though. Just give them a way to ask their questions.
Include the names of the people that made the decision on the record. This way, they know who's able to answer their questions.
Then it all comes down to asking the right questions. "Can we use this?" is pointless. How should they know? They have no idea about the current project and they likely made the decision record months ago. Instead, make the question specific. "Our flow has a time limit, which this decision doesn't cover. Does that change the approach?" That sounds like something concrete they can discuss.
This doesn't make the people who wrote the record a permanent help desk for everyone. If a question reveals a missing boundary, make it a point to add it back to the applicability section. If the answer explains a trade-off, add it to the rationale. If it exposes an assumption nobody tested, write that uncertainty in there.
There's no point in saving every conversation around a decision record. Think what might help someone else beyond the person asking the question. That should go in, but drop everything else. If it's important enough to include, it'll come up again.
Each useful question should make the decision record a little better.
Otherwise, we've replaced repeated design work with repeated explanations. And that's really no better.