2SLGBTQIA+ is a result of being more inclusionary, and it is the standard for the Canadian government. The 2S at the front represents two-spirit people, which is a term that Indigenous people use (also why it was placed at the front, as a sign of respect since they were here before everyone else). The QIA+ are literally additions to include queer (which is a catchall), intersex (who were previously medicalized and excluded), and agender/asexual/aromantic people (who have historically been excluded/ignored), and the + obviously is to include anyone who doesnt feel reflected by the other letters. This is literally the least exclusionary way to do it.
GSRM has been attempted many times but framing people as minorities when providing allegedly inclusive terminology is generally out of fashion.