that person is STRATEGIC VOTERS, who are about 90% of the electorate. even if you want to vote honestly, you're still subject to the whims of other voters.
indeed, practically the only thing that matters in a voting method is the aggregate affect of what it achieves in light of other voters. YOUR vote will almost never make a difference. you could upgrade voting methods in exchange for giving up your right to vote, and you'd still be drastically better off.
it doesn't really matter how you define "honest". what matters is how people actually vote. the only really crucial distinction for "honest" versus "strategic" is that "honest" can't consider viability. in the simulations, we just use "approve everyone you like more than average". optimal strategy is to approve everyone you like more than the expected utility of the winner.
https://rangevoting.net/RVstrat6
with FPTP, strategic voting means NOT voting for your favorite. so at the very least, you'd "vote for the person you'd normally support under FPTP, _plus_ everyone you like better".
but in real life, a lot of people will use intermediate scores.
there's no such thing as "acceptable" or not, there are just utilities and _relative_ satisfaction. you want to get the most satisfaction possible from the options you have.