Q.Indoor yucca plant
I purchased an indoor yucca that looked a little like it was struggling. I brought it home and transplanted it to a larger container using indoor potting soil, and set it in front of a bright sunny window. It has slowly been losing its leaves, as they are all turning yellow, then finally brown, dry and brittle until they have to be removed. No matter what I have tried, it continues to have droopy leaves and it looks worse than when I purchased it. What should I do to save it from worsening and/or completely dying? Does this plant go through a dormancy period?

If the plant was all ready in a stressed state when you purchased it, then it was repotted and moved to a much brighter location it may not recover.
I would move it to a partial sun location and verify the soil that you used to pot the plant is a good quality mix of sand and peat.
The new pot size should have been only 1" larger in size then the original pot.
Yellowing leaves generally will indicate a watering issue, too much or too little.
Here is a link that will refresh on the care requirements.
https://www.gardeningknowhow.com/ornamental/foliage/yucca/growing-yucca-indoors.htm