https://www.cbr.com/why-gloria-was-recast-in-golden-girls/

Dorothy's sister, Gloria, is one of the few notable recastings in The Golden Girls (https://www.cbr.com/tag/the-golden-girls/)' seven seasons.

Correct me if I am wrong but the article never is specific why. It only speculates there could have been a scheduling conflict?

I always assumed the show did not care and barely anyone would remember Gloria from season 1. Its not the first and only time the show did this. When Big Daddy appears he is played by another actor. But he died so they had to go with another Big Daddy the next season. The original Big Daddy was the mayor in the movie Jaws.

We only see Dorothy's daughter in season 1, correct?

Its nice seeing Gloria get another show.. She was excellent with Archie and Edith!