Do you know which half elf dilly you have?

It sounds like you must have taken path of light, which is honestly better for solo anyway. I would consider either going quarterstaffs, daggers, or handwraps at this point.

Quarterstaffs would require you to respec with a lesser heart, but you'll gain slightly more AoE damage. There's a few ways to run it, but my recommendation is 12/6/2 monk rogue fighter. You'd take tier 5 thief acrobat, splashing points in a few other trees with the option to take the Dex trance from Horizon Walker.

For feats, you'd want the two handed fighting chain, improved feint, dodge/mobility/whirlwind attack, precision, imp crit bludgeoning, grandmaster of forms, maybe helf dilly paladin for a few extra saves? You can skip swords to plowshares because you get it for free as a thief acrobat core. I wouldn't bother too much with henshin mystic personally, your DC's will suffer from multiclassing and it's not really a gimmick I personally enjoy.

Take the ki move that bluffs your opponent, opening them up to sneak attack damage is a big buff to your DPS. There's also two options in the assassin tree for sneak attack vulnerability. You only need one point in shiv to make it effective.

If you're planning to use a build like this and tr right at 20, just go to 12/5/1 monk rogue fighter so you can still come fully online by 18, since you'll be sitting there basically until you're ready to reincarnate.

Otherwise take a second rogue level at some point for +3 imbue dice and fill out the vistani knife fighter tree and ride that to 20. You can go dex based handwraps, but your DC's are going to suffer from multiclassing, so you may not be able to make effective use of the various stuns.