The reason you see "2S," which means "Two-Spirit," in Canada is because it highlights First Nations people in a country which has oppressed its indigenous population for centuries and which tried to erase the cultural identities of those peoples, especially if those identities happened to include third genders or something similar.

So putting the 2S at the front centers that struggle, like how lesbians got to be in front of LGBT because of their work during the AIDS crisis.

2SLGBTQ+ is used mostly by the CBC, since it's the most Canadian version, highlighting two-spirit as something culturally distinct. But in practice, we all just use "LGBT+ or "LGBTQ".

Kinda like how we all use "MMIWG" and not "MMIWGA2SLGBTQI+P" https://mmiwg2splus-nationalactionplan.ca/eng/1670511213459/1670511226843

(Also to be pedantic, it's an initialism)