They are gonna redraw the congressional lines. If I were you I’d bite the bullet and vote RINO on that one issue alone.
If you wanna make a “statement” voting for a third candidate on the ballot is the only way. Sitting out, casting a blank ballot or voting for a write in candidate that isn’t actually running (or doesn’t exist eg Mickey Mouse, I don’t know about VA but in my state you have to be a registered write in candidate and I caused them problems when I wrote in “Dick Nixon” for city treasurer once) would barley be noticed.
If there are only the Republican and the dem running then you are out of luck and might as well just stay home if there is truly nothing on the ballot you want to vote on.
But if there are 100 ballots and 48 voted for Candidate A, 45 voted for Candidate B, and 7 cast blank or write in ballots, the winner gets 48% of the vote, not a majority. Paeronally, I think it makes a difference rather than the winner getting 55% and being able to claim a mandate.