According to Grossman: "We have no information about Rashi's mother either. His considerable concern for the dignity and rights of women allows us to infer, however, that his mother was devoted to her son and that he loved and esteemed her. Rashi's maternal uncle was a renowned scholar, whom Rashi referred to as 'Rabbi Simeon the Elder. It is not known for certain who he was, but chronology makes it evident it was not Rabbi Simeon ben Isaac ben Abun, the greatest liturgical poet of early Ashkenaz. The uncle studied with Rabbenu Gershom in Mainz, Germany. Rashi relied on a halakhic work he had written and probably studied with him. It is quite possible that the uncle's influence contributed to Rash's decision to travel to Mainz and study in its yeshiva. Several other of Rashi's relatives are mentioned in various manuscripts, but their identities are unclear." Grossman, “Rashi” (Littman, 2012), pp. 13-4
Meanwhile, I add that I know of no reference by Rashi himself in his voluminous writings to being descended or in any way related to R' Shimon HaGadol.
In view of this information, the parentage of Rashi's mother as shown on the Geni tree (as of this writing) should be severed except to show a grandfather of unknown name and descent, and an uncle (son of the unnamed grandfather and brother of Rashi's mother) named R' Shimon the Elder.
Is there any reliable evidence to the contrary?