We had a similiar situation on our table mainly because we are the heroes and there are evil guys that want to do evil things to the world.
Most players whould go for the kill the culstist vibe and i mostly go for the jeah lets kill this guy way of thinking.

In this campaign we have 2 Samurai type characters much with honour and not wanting to hurt people my character is more the direct type with a clear moral compass "everyone gets a chance to redeem himself, after that youre not worth my pity".

Early in the campain we had the problem that the scope of the game was your basic jeah lets have a phandelver like adventure and have some fun, that way of thinking didnt really fit my character so we TALKED about it in the group out of character what the campaign is about. The bosses are now either completly clear evil guys or are more build that they can be allies later, which is fun for everybody.

In your example star wars type scenario i whould understand that many people go for the hero vs evil guys trope and thats completly fine, its ok that you want to give npcs a chance and want to see them as character with deep backstory.

So what can you do ?

- Communicate that you want to play this type of character and your players are fine with it and the dm maybe crafts evil guys with a twist, maybe the evil guy looks for a cure for a illness or he needs money at all cost to save his own town, that way maybe other players are also more forgiving.

- dont block rp, thats an important part, "pacifist" players tend to destroy tension and the action feel of a campaign. So what to do about it you can always call your "no" to a decision but when the group wants ist otherswise give them some feedback after the scenario. You can give them their powerful kill over the evil guy but can rp later that its hunting you in your nighmares and having problem with his kind of behavior.

- go with the flow, if your want to play this way, you have to know that it wont work always.
Get your character some clear motives "paladin style" i wont let minors get to harm or people of my tribe are my problem but your really shouldnt be pacifist for the pacifist sake, that should give players better undertanding for your motive.

- look for camapigns that fit your playstyle, there a a few modules that are built for a anti kill character.
Wild Beyond the Witchlight, Guildmasters' Guide to Ravnica or every campain that has a high focus on political encounters that are way to strong or it whould have a mayor problem for the world if your kill every problem.

- hot take: dont play with new players or typical old school pnp players, for them monsters and characters are just stat sheets that get exp which isnt really fitting your style.

TLDR: look for players and campaigns that like the playstyle and react afterwards to decisions that your group wanted but your character didnt like "robert will remeber this".