Originally Posted by
RogueJK
No, there's no juggling needed. Just take a hand off the 2H weapon (no action required), grasp your spell focus/component pouch and/or perform the somatic components (no separate action required since it's part of casting) and put your hand back on the 2H weapon (no action required). You don't even have to spell it out every turn, since it's all non-actions. It's just assumed as part of the process of casting while holding a 2H weapon.
Per the PHB errata and Sage Advice, the Two-Handed property is relevant only when you attack with the weapon, not when you simply hold it. You can hold it in one hand while casting, then regrasp it in both hands to attack or ready yourself for potential OAs. Switching between holding it in 1 hand and 2 hands is a non-action, and can be done freely.
Compared to something like a non-Warcaster TWF or sword-and-board arcane spellcaster who's having to do the actual juggle of drop a weapon (no action), cast spell with free hand (action), then pick weapon back up (using your your lone free Object Interaction per turn). Those are the only instances where being a Swords Bard would be helpful to prevent "weapon juggling".