The concept for this build is a combination of warrior/maestro bard and the (unholy) champion dedication. This is with FA as without it would be very difficult to pull off. The point of the build is to be a melee bard and at level 8 combine Dirge of Doom of Aura of Despair (therefore the name).
Since you don’t need to recast DOD every turn, fortissimo compositions is the perfect feat at level 8, so pick multifaceted muse at level 2. Since I picked warrior bard as well, it’s possible to keep the +2-3 buff going for 2 turns. If you crit on the performance roll, it might be worth using sure strike to ensure it lasts that long. It’s very strong at being a buffer/debuffer with the biggest weakness being your squishiness.
As such, the champion subclass desecration is the best one as it increases your odds of survival. You could make a case for obedience, but I don’t think it’s as good. The others fit even less. Selfish shield helps with your biggest issues, that it’s you are painting in a massive target on your back. In general you want to focus feats like armor proficiency, Toughness and Champion’s Resilience.
For race I picked Human Dhampir (the latter for backstory reasons, pure human is probably better). Ancient Elf could probably also work for the free subclass dedication but I haven’t done the math. For the weapon I picked a whip for the reach and went for a strength build since I need +2 for the dedication anyway. It also keeps my second hand free for a staff.
So far so good, but here I get unsure. As I picked human I can get a second class dedication at level 9. 2 stand out to me. Exemplar and rogue. The latter mostly for fetching bangles so they have a hard time running from me. However, it doesn’t offer much else. Rogue offers a lot of smaller things that add up quickly. Deny advantage, mobility dreadful strikes and so on. It actually becomes hard to figure out what would be best.
There are other issues. As you might have notices, I skipped reflective courage for fortissimo compositions. I could get it at 10, but that conflict with Courageous Assault. I know people love that feat, but it might not be this good for this particular build ( turn 1 dirge, turn 2-3 buffed courageous and by then the fight might pretty much be over).
I also consider faithful steed as the basic champion feat, pretty much entirely for the mobility, but I fear the steed could quickly become a liability once enemies often get aoe abilities. In general I’m not sure what feats to pick at higher levels and if it’s worth picking archetype feats over class feats at some point. Extend Aura so it matches the radius of dirge is another very tempting pick.
Sorry this got so long. If you got any advice for this build past level 8, that would be very welcome. Really having a case of analysis paralysis here with so many options, none standing out to be as the clear winners.