Help - Build Idea - Stealthy Psi Warrior?

Starting a new custom campaign at lvl5, rolled stats: 9-12-15-15-15-15 (yeah that's a lot of 15s, I know!) The thing that I know is that it's going to be quite combat heavy, pretty much a long rest at the end of most sessions or at least a short every session, and I don't expect the campagin to last long (probably won't reach lvl10)

I'm liking the Psi Warrior flavour, and found and interesting build idea from d4's Optimized YT series, which I very much like the concept of, but I feel like the soulknife rogue dip is interesting for the sneak attack, but other than that, you're losing on Extra attack and an ASI if you'd go PW 5 from the get go.

I'm a bit lost honestly, especially since you can't stack the pool of die for both subclasses, although I gotta say, I would use the PW ones more for sure. Would there be a way to play into the mind psychic, lurking Psi Warrior? I'm not necessairly sold on Githyanki nor on a melee/range build so any suggestion is welcomed!

I'm seeing this character similarly to a lost child, very immature and likes to play mind tricks on people, allies included. Something that isn't the face of the party and has rogue-ish like tendencacies.

The first thing I was thinking of was a Shadow Touched (ft lvl4) INT/DEX (or STR, lets be real, with those rolls, I can do whatever I think) warrior that can go invisible, misty step, high mobility kinda stuff. Kinda similar to Nightcrawler in Xmen maybe? just pops in and out of fights, but just without the beastial form?

Anyhow, I feel like I'm rambling a bit here, so please feel free to help me out :D Thank you!!