New campaign spinning up and wanted to play a gish. Decided on a pact of the blade warlock and started exploring options. Here is what I have so far:
1 Fighter start, then warlock x. Toying with the idea of either GWM PAM for nova damage or to go warcaster/sentinel and play around controlling and slowing the enemies. I want to do a undying warlock because I like the theme and started looking through spells to plan out choices down the road.

Spirit Shroud from Tasha's seems like a great fit thematically and mechanically as it provides extra damage and a slow effect. Paired with the Slasher feat and I now have the ability to really *HAMSTRING* an enemies ability to move through the fight. With warcaster repelling blast I can even slow them down, then blast them away if they try to attack an ally.

I think the idea is fun but it has issues, the first of all is it's pretty MAD. I would need cha for spells/saves, con for HP and concentration, Dex for armor and probably some str for melee attacks. The second big issue is the amount of feats the build wants to use: Polearm Master, Sentinel, Great Weapons Master, Slasher, Warcaster, Resilient Con are all great picks for starters.

I got an amazing rolled array of 16,16,16,14,14,12. I also was permitted to use the Tashas Custom Lineage for my race. I went with 14 str, 16 dex, 16 con, 12 int, 14 wis, 16 cha 2 from the racial to 18 cha. For my racial feat I can grab any one of those listed above, grabbing PAM to start.

My questions then are: What spells do you think I should focus? Armor of Agathys, Mirror Image, and Blindness/Deafness seem like solid picks as non-concentration spells. Spirit shroud is our main concentration dump. Are there any others to consider? Which invocations would be good for this playstyle? Which feats are the biggest priority? There are so many options to consider I'm having a hard time sorting out which things I should focus on and which ones I shouldn't.