With the new DCC friendly switches with isolated frogs do you still have to use insulated joiners or plastic filled gap on the frog ends of both tracks when you have a frog to frog situation such as a siding or A/D track?
With an insulated frog - no. Provided you keep your feeders straight. I even put a set of feeders in the frog to frog connection so I don’t rely on whatever stips of metal or other connections are built in to the switch.
–Randy