Best class to max out Illithid powers?

I skipped the icky worms on my first playthrough on Tactician, and intend to go full all-you-can-eat shrimp buffet on my Durge Honor Mode run. (she's a gnome who wants to get taller by any means necessary, including but not limited to becoming an Illithid.)

Right now I'm eyeing Warlock or Bard, as I skipped those classes entirely on my first run through, but I'm open to suggestions. Considerations for early survivability are probably going to matter more, but if I get arrested or start a fight from stealing too many worms, that might make things worse...