In my honest opinion, I would rather have an LGBTQ+ category. Since, you know, it would cover a whole sexuality spectrum and no one will feel left out or feel that tapas somehow disrespect the sexuality because they didn't make it as a category like BL.
And if they want to consider another suggestion of mine, it would be best to set it as a secondary genre. It's not like everything BL or go or lgbtq will necessary about the LGBTQ revolved. Maybe the lgbtq is just an spice that was added but not the main ingredient (Ya, well, got want I mean?).
If they can't let the non premium creator have 2 genre on one work, just let the BL to be set as secondary genre when it was chosen, thought It might not be easy on the coding part, so just don't mind me lol.