Leia's death and Jedi funerals

The simple answer: she wasn't a Jedi. Although she was trained to use a lightsaber, she had no Jedi master, she was not trained to use the force, and she had a husband and a family. (which is forbidden for Jedi) The Jedi ceremony is probably reserved for Jedi only. Lightsaber training and relation to a Jedi does not make her a Jedi.

Leia specifically chose not to be a Jedi because she sensed doing so would lead to the death of her son, as explained by Luke in The Rise of Skywalker:

"It was the last night of her training. Leia told me that she had sensed the death of her son at the end of her Jedi path. She surrendered her saber to me and said one day it would be picked up again by someone who would finish her journey."

As such, there's no reason she would be given a Jedi funeral (and doing so would likely have been disrespectful of her wishes).