The feat I took on my current Damphir Long Death Monk was Fey Touched with Hex to boost a 17 Wisdom to 18. Then I took a Wisdom ASI at level 8. I considered taking another half-feat in Shadow Touched with Cause Fear, which is very appropriate thematically, but I thought an ASI was better.
Being a Dampir also lets my fanged bite scale with the Monk Martial arts die and if I am below 50% hps the attack roll is with advantage.
As far as ki, I use stunning strike and focused aim a little bit. I almost never use flurry and I think that is a waste of ki generally. Through 8th level I think I used FOB twice total. Once to try and finish an enemy close to 0 to get the temp hps from Touch of Death (which I was unsuccessful at) and once to get as many hits as possible on an enemy caster to break concentration on hold person (which I was successful at). Most of my ki goes to patient defense or step of wind. If I was playing a different subclass I would probably be using a lot of it on a sublcass ability, but the 3rd and 6th level Long Death abilities don't use ki.
Another feat that works well on a Monk with an odd dex is Weapon Master because of the Monk martial arts die and Dedicated Weapon. I think this is the only class that really benefits from that feat.
TBH as far as other martials go, I think some feats are awesome, like Sharpshooter, but others, specifically GWM, PAM, Crusher and XBE are rated very high by many and do well in the White Room, but are not that powerful in play because they limit weapon options and make players less effective overall when the magic loot they find does not compliment their feats.