Designing a to be arcane trickster who has lived and worked in a library, was originally going to make them human with the magic adept feat, but am debating between that and being a high elf. In any case was looking at touch cantrips to fill in the melee hole that the character has, as they prefer fighting at range as melee is scary. Unsure of which spells fit this niche at the moment, only one coming to mind is shocking grasp from the top of my head. Where as the rest of their spells will be in the limitations of arcane tricksters if they have any other than just one. The text on sneak attack says that you know how to strike subtly and exploit a foe's distractions, which seems the way a rogue like this would attack using such touch attacks, aiming for weak spots and quickly darting in to deliver the spell and getting back out, much like a rapier thrust. Like in the case of shocking grasp, aiming for surface level nerve bundles, open wounds, or some other target to maximize the attack. If stun batons existed I would just use that and call it a day, but they don't in this universe. As a high elf shocking grasp is the only spell that fits the bill, with magic adept there are a number more.
That is the rough idea i'm working with currently. Personally I'd be fine giving up the scaling and using it like a rapier with whatever magic damage type the spell uses. It does open up weaknesses to anything with mage slayer.