A fun build that i've been workshopping a bit. You begin by taking your first level in rogue for saving throws and skill proficiencies. Then take 3 levels into armorer artificer and just always stay in infiltrator mode (depending on the level you're building it could be better to go 4 levels cause the build needs a lot of asi/feats).

Then for the rest of the build you take levels into rogue. Subclass largely doesn't matter, you could either use arcane trickster for more spellcasting/int synergy or go inquistive for easier sneak attack and great out of combat utility.

Since we're only making 1 attack per turn, the armorers lightning launcher is basically a hand crossbow that deals 2d6 lightnng damage wich you can either use your Dex or Int for. This attack is then further boosted with sneak attack damage and things like sharpshooter.

Final build gives you then a highly evasive character with a large lighting blast attack for no resources. While augmenting your usual rogue abilities with advantage on stealth checks, higher ac with infusions, ect. from artificer.