I don't get it.
In 40 years of playing D&D I can never remember any characters with any kind of sexual preference.
I have never played a heterosexual character, I have never played a bisexual character, I have never played a homosexual character, I have never played a cisgender character, I have never played a transgender character. For the most part I have not DMed characters that fall into those buckets, labels and stereotypes, nor can I remember other players with such characters.
This is not a "thing" in the games I play and essentially every character I have ever played has been asexual with no defined sexual preference. To date, they have all had an identified a gender. So not binary, but not necessarily cisgender either. There were male characters and female characters, but I never put any effort into making them cis or trans and to be honest I don't know what the difference would be if I did. How is a cisgender Tiefling woman different than a transgender Tiefling woman. They are a female Tiefling regardless! To be clear I have played female characters with beards (mostly dwarves), and men who could not grow facial hair (mostly elves). I have played weak and small men, strong and huge women and vice versa. Were they cis or trans? I have no idea and I was the one who created and played them!
I just don't understand what exactly this is about and what exactly an "LGBTQIA+ setting" is as my games, including games in all published settings have been this way from the beginning.
Now if this is talking about discrimination against certain players, that is an entirely different story, but if we are talking about the game world and characters in the game, I do not understand what it means or what it is supposed to mean.