I'm probably not as far as you, only level 4 and just now getting into underdark for first time. My current group is Bard 3/Rogue 1 Tav, Gale, Karlach, & Shadowheart.
Shadowheart with trickery domain will be a secondary stealthy to support your main. Trireme already broke down most abilities. But one spell you get at level three helps a lot. Pass without a Trace, +10 to stealth checks, last till long rest, & is a aoe around her. This with her high wisdom helps on spotting traps and such.
If you are not big on scouting or stealth play, it be a no Brainerd to respec.
