Is there a way in the subclass builder to add an option to change between hybrid and normal forms similar to the Lycanthrope Blood Hunter? I'm attempting to make  a balanced and user friendly lycanthrope subclass for the druid. Any help is appreciated, thanks in advance.

I'm not sure this would work but homebrew a monster and add it to the druid shapes might be the smoothest solution.

As you need to bump it in power just create a new versionl

The usual workaround for having some sort of modal toggle that affects stats/abilities on the character sheet is to homebrew a magical item that can be equipped or unequipped and which carries the stat changes from the modal ability on it.  If your hybrid form gives you increased Strength and Constitution, resistance to basic weaponry, vulnerability to silver, and an enhanced claw attack, you can do everything but the claw attack on a custom Wondrous Item.  When you equip/wear/wield it on the sheet, you get your changes.  You'd have to do the claw attack as a custom action on your specific player's sheet, unless you can map any attacks you want the form to have to an existing weapon.