I have grown peppers from seed as well as transplants from the garden. They both do well off season indoors. They are in front of a glass patio door facing south west, and have grow lights for dreary days and extending the daylight.
I keep the grow lights on after dark to extend the daylight hours to mimic summer time. They bloom pretty well, and are self fertile. I do plant them in smaller pots than I would if they were outside. The fruits tend to be a little smaller is all, but the perfect size when making a stir fry for two.
It’s encouraging to hear that your indoor peppers do well. I hope mine do too.
I’ll post pictures as it grows/flowers/fruits (I hope). I want to bring them outside eventually, we can put transplants out in the ground here as early as mid-February (depending on temps of course).