Disclaimer: I'm no expert and I have yet to beat UnderRail in Dominating, but this fast theorycrafted build should, with the exception of areas that have specific agility or strength checks to be accessed, give access to as much content as possible. Note that points put in diplomatic skills in the build link may be more or less than the maximum needed to pass all checks.
*Ninja Edit: Short version - Stealthy high Will psi builds are still the way to be able to do most quests and most lore. Builds that have WIL as secondary stat aren't advised for such purpose.
Psi still is strong and the Nerfs mostly affect multi-school generalist psionics-only builds. Here is a suggested Stealthy mind controller, grenadier and knife thrower glass cannon who yells too just for the sake of it and should be able to pass most dialogue checks in the game. After Depot A or even before if possible, find the recipe for and craft shock shurikens, they will be handy in addition to EMP grenades against robots and their damage scales with throwing skill. Going full specialist in psi means you never have to worry about changing innervated psi abilities except when learning new ones.
https://underrail.info/build/?HgMIBgMDDwgAwqAAAAAAwqBqeAAAO1RBP0jCoAAAAE9SRCQ5K0QWKgU-URohZsK8PyNkwq7CncOHwrdscsK74p2CCuKlvALiqLsD378Start with 7 DEX, 10 WIL and 8 INT, raise WIL every time except at level 12 where it should be DEX for Fatal Throw. Use psi beetle enhanced biohazard vest as main armor, with a spare galvanic one for some areas where enemies with shock attacks are plentiful. With Nimble, 6 AGI, full points in Stealth and black tabi it should be possible to sneak around wearing it despite the 15% effective armor penalty, at least in lower difficulties than Dominating. You may replace Nimble with Quick Pockets if you prefer one more combat utility to more protection and psi bonuses with the same armor penalty but IMO it's not a good trade. 17 WIL is most certainly enough to pass all psi-related WIL checks that give glimpses of the lore only accessible to psychics, I'm not completely sure but it should suffice.
Maybe going full specialist in another psi school is better, like a 10 CON 10 WIL 8 INT at start methathermics "tank"* that brute forces through high heat and cold DR/DT foes, but I think TC + throwing to deal with robots and CC is the strongest choice.
*Too low STR for metal armor to be a true tank in this example, for most typical high STR psi builds are either unarmed psychokinesis monks or
hammer wizards (link is a guide to all hammer builds in general).
