Q: Wouldn't I want to "bury" a strong second choice and give a higher score to a weaker opponent to help my favorite win?
"Burying" is where you promote an electorally weak third choice candidate over a electorally strong second choice, in the hopes that will help your first choice candidate win against your weak third choice.
Here’s the problem with that in STAR Voting: if you think your first choice can’t win head-to-head in the runoff against your second choice, that means you think your favorite is vying for the second seat in the runoff. In that case the worst thing you can do is add points to a candidate you like less than both your first and second favorites. If you aren’t sure your favorite has a shot at the runoff, you’re very likely to give your strong second choice at least one point. Adding any support to a less preferred candidate in this scenario simply increases the likelihood your own favorite will be squeezed out and that your runoff vote will go to someone you really don't like.
Fundamentally, for the "burying" tactic to work, voters from opposing factions have to gang up on a well-liked consensus candidate by supporting the opponent they really don't like higheron the ballot than their true second choice. But if either of those factions actually believe that the opposing faction is going to adopt this strategy, their own best play is to simply vote honestly in order to give their own favorite the best chance of winning against the (now diminished) consensus choice. For "burying" to work in STAR, voters of true opponents must work together to be dishonest on their ballots, yet if one faction decides to be honest instead, the honest faction will gain the significant upper hand.
Conclusion: "burying" is not a viable tactic in STAR Voting.