I use queer as short for genderqueer, but I use gay as short for lgbtq (minus the ia+ in this case) and I do respect and understand if someone does the opposite and uses queer as the blanket term for lgbtqia+, that's fine. When I was growing up and it was LGBT, queer was usually conaidered an insult (as kids we played Smear the Queer, which probably helped me come out of the closet tbh) But it's literally in the acronym now. It's not a hateful word, but could be used hatefully on a rare occasion.

I use queer when referring to a bunch of different sexual or gendered people (eg, some bi people, lesbians, an asexual person, etc etc). I use LGBT+ or simply LGBT when in contexts that include audiences of all orientations including straight, to not create confusion. LGBT+ includes everyone without being excessive imo. The only ones I see doing more than 4-5 chars anyways are usually straight or straight-facing entities (eg, groups, news stations, etc) referring to us as an entire collective. To me, going for 7+ chars in an article feels kinda like unintentional pinkwashing, but maybe that's just me x3