Looking for some insight to an idea I had. I am creating a Champion Paladin that will be a tank. Picking up shield feat where I can, but also looking at Demoralize activities. There is a swashbuckler Feat (Antagonize) that causes enemies to keep Fear 1 unless they attack my Champion, which is what I want. Has anyone tried this and is it worth it?
I haven't tried it, but had considered it. I do think it's worth two low level feats (w/ other Swashbuckler feats lined up too). On a Champion, the Dex & Cha costs a little, yet opens up lots of non-combat utility and makes you a bit better at one weakness, ranged combat.
That said, party composition and synergy (and campaign appropriateness) might override, but in a typical party both the other players and their characters will appreciate such a partner-minded debuffer/tank/emergency healer/(backup) face.
Since you're already picking up some Dex, you might want to consider using a throwing weapon w/ 18/+4 Dex. It wouldn't need to have much range as you'll still be in the skirmish. It'll save you actions so you can Strike/Raise Shield/Demoralize more often, and melee opponents you scare will have to waste actions coming to you. (Also that Dex IMO patches all the flaws Champions have except damage output, but your contributions will more than make up for that...again assuming the party meshes well: in this case contributes lots of offense).
You may run into the problem that most early level swashbucklers have. Enemies can simply perform a hostile action on you once to remove their fear and since they are then immune you cannot "taunt" them with demoralize again. Swashbucklers at level 9+ can finisher enemies to "reset" this immunity but you need to find other ways.
You can mitigate this in two ways I think. One is going the hobgoblin ancestry for remorseless lash. This will extend the frightened condition as long as you hit them leading to two conditions needing to be satisfied in order for them to lose the frightened condition (you missing and them not hitting you).
Or you can take the Aura of Despair feat if you are an unholy champion of justice. Meaning that creatures who don't target you also have to move away from you if they want to lower their frightened value.
One could argue that if you are spec'ing into either of these options to bolster antagonize then you may be better off just not going antagonize but it could still be a fun build that goes hard into demoralize.
Probably synergizes well with the champions that have reactions for being hit. I like the idea of pairing it with Aura of Despair to make it super inconvenient to remove the condition.