Chem, Energy or Snipers are mainly stealth builds. Chem pistols builds are usually Versatility, because of the high AP cost to fire them. So if you want solid dps, you need DEX. After that you can go Survival Instincts glass cannon, or 3 CON but higher INT and Mad Chemist for better Damage Over Time and crafting in general, also 6 PER for Ambush - works great with Incendiary and Molotovs. There is a Chem tank build on Youtube, but it looks painful to play as you will be subject to all forms of skill reduction (when it's already hard to hit with Chem Pistols), AP reduction and CC's.. don't do it on DOMINATING 😆
Energy Pistols - you want high INT for High Technicalities and crafting in general. Also Ambush or SI again. But you also need DEX to reduce costs.. so Versatility again. Or a DEX/PER build, which leaves no place for CON again.
Remember DOMINATING enemies have even MORE Evasion - versatility builds already struggle and without Ambush - even more so...
And sniper without Stealth... is a no go. You need positioning, you want Snipe and Ambush, so that your shots 1 tap for Shooting Spree. You can again try going SI, and there is a strong showcase by KnifeGaf of Low INT, SI sniper build.. but it is still Stealth. You need Stealth with those builds I am afraid, for DOMINATING at least.
Ballistic Pistol build on other hand, with high initiative can do a non-stealth and non-glass-cannon build:
https://underrail.info/build/?HgMQCQcDAwVGMgDCoMKgwqAAADIoKHh9PSYwAAAARgAAWBfCoxkww5FbK07DkiTChzEWS0HCsyc54qCKBeK1rgXivYQF378You can reach 59% Crit Chance with (10% Base + 7% Reckless + 18% Goggles + 15% Focus Stim + 9% Infused Rathound Leather Armor), use Hammerer frames for 125% Crit Damage boost.. yeah, it looks like a fun build to play.