As a general rule, most things flourish far better outdoors.

I do know our SE heat and humidity can be brutal though...so I don't have any good direction to suggest.

I bring mine indoors as houseplants over winter. They do like a bright sunny window, and I find they do stretch out a bit. I usually cut them back drastically when it’s time to bring them outside again.

Are they showing signs of being unhappy outside?

If they are not happy outdoors then by all means bring them in and put them in a sunny window. Victorians grew geraniums on their window sills to brighten up their interior decorations because they grew well indoors and outside and were easy to care for. Do cut them back if they get leggy and they'll bloom again outside when the weather is cooler