I've seen a compilation of data someone put together with fanfiction shippings and it shows an overwhelming popularity for Shadowheart as lesbian or bi. Shadowheart and Lae'zel is the most popular by far with more than twice as many shippings as Shadowheart and Karlach that comes in at second, with Shadowheart and Female Tav being the third most popular.
That's a very true point. I think in terms of her being romanced by players in-game, it's probably going to be mostly by straight men since that's going to be the majority target audience for this game (that is not to say that in terms of fanbase bg3 has clearly been very well received and loved by the LGBT community) but in terms of an active fanbase, the lesbians are the majority loving her instead.
