I am sad to report we lost our girl, Bluebonnet this morning.
She would periodically release a batch of eggs (3 times since we had her). Every time she would get lethargic the next day, but the day after would be back to her active, begging for food self. Two days ago she released a batch and we found her dead this morning.
I have no idea if this is normal for female bettas to release eggs every couple of weeks, and whether or not that can cause stress that could lead to death, but we're trying not to beat ourselves up too much about it.
I'm not sure where to go with this 3 gallon cube from here.