No biggie. It's no life-defining magnum opus or whatever. You could be somewhat more specific though. Is there a way to improve it, you think? If it is fundamentally subpar, why? With stealth tranquility psi, I only see 3 con being bad until you get mirror image (or however it's called in underrail) and a half-decent shield. After that you should not be hit very often.
Mirror image not going to save you from a lot of attacks. Anything without chance to hit will ignore it ( aoe, psi abilities). Or at least that's how it works for enemies. I killed a lot of natives psykers while they are under mirror image with 1 hit.
So, about build...
I just don't like 3 cons builds. It's pretty much quick save/quick load. It could work for high initiative build tho. Not sure if your initiative high enough. So as soon as you detected or after your first turn you can die in 1 hit. And there a lot of things that can one-shot even a 10 con max lvl psi build... Like new native bosses. Defending beach in dlc will be a challenge, since crossbows could oneshot you.
But maybe you can pull it off - i know it's possible to beat dominating with 3 con. But if i remember correctly, that guy who did it also had max dodge/evasion/stealth. There is also a psycho high con/stealth build, that relies on survival instinct which could be a good damage boost for your build...But you want to play with tranquility, right?
Second - if you are using psi as main damage source, there is no reason to use melee. I have no idea how your spear is going to hit with stats/feats like you picked, but i'm sure that damage would be much, much lower than your "spells". Why use spear then? Why not use grenades/traps instead? You know there is will based "infinite grenade" in dlc, right?
You also mention this "Targets who are immune to Neural Overload get psychokinesis with Force User and energy edge spear with Impale". I...don't want to say something stupid, but i have doubts about this. I'm sure there better people who can say if this is a good idea. But would like to see how you are going to melee naga guardians. (i know you can avoid them, but still). Your biggest weakness is range of your neural overload, imo. And you need to beat dlc for that sweet +1 range.
Also - no lockpicking? No mercantile/persuasion? Can't remember, but don't you need lockpicking for abram quest or you can kill all guards and still get invite to oculus?
Sorry if this hard to read, i'm not a native english speaker.