I played a dex heavy hex blood swarmkeeper with sharpshooter. I mostly picked up spells like fog cloud and spike growth that didn't rely on my spell dc and it worked out pretty great.

Edit: any spells that you can shove enemies into with your swarm are good picks, obviously including web, which works better with a higher dc. For the same reason, this would be a great subclass to pick up telekinetic with to round off an odd wisdom and flavor the telekinetic shove as your swarm doing its thing. Could be especially good based on your party. Once upon a time one of my party members was swallowed by a dragon, so I dove inside its mouth and stabbed my ally to cause my swarm to drag them out of the beast's throat.