These numbers (if correct) are really extraordinary, and pose all sorts of uncomfortable philosophical questions for pretty much everyone's assumptions about gender and sexuality. Even if the numbers are wrong (e.g. what people report in this way is not a good way to capture people's actual sexuality as opposed to how they like to linguistically construct their sexuality) it poses major questions.

The biggest question is: why so heterogeneous? Trans people do not remotely look like the population as a whole. Why not?

Is it biological? Does that mean there are a variety of different flavors of being trans? If yes, do they differ in other important ways? Do we need to distinguish and treat the groups differently in select circumstances, much like we treat men and women differently (in cases where we can't afford individual attention)? Or does whatever differs in trans people from cis people also tend to scramble the normal innate sexual orientation (with somewhat random outcomes)?

Is it sociological? Does that mean that waaaay more of sexual identity is culturally determined than, for instance, the gay rights movement would have had us believe (honestly, let's say--it wasn't culturally determined for them), and that the Christians were not just fantasizing about about culture "corrupting people's sexuality"? Or does it mean that trans people, possibly because of their inclusion as part of the LGBTQ movement, feel compelled to report a more wide-ranging and fluid sexual orientation than they really feel (i.e. if they were not part of that community, the categories would be tighter)?

Or some combination of biological and sociological?

Or is the study just wrong in one of the ways sampling can go wrong (small sample size, unrepresentative sample, etc.)?

There are other reports that paint a different picture--see https://www.nature.com/articles/s41443-020-00402-7/figures/3, for instance, which has rates of 8% (strongly) bisexual, 6% asexual, 53% (predominantly) heterosexual, and 34% (predominantly) homosexual at the initiation of hormone therapy. Note that the titles of Figure 2 and Figure 3 are swapped (?!--how does this error make it past editing??!), and I calculated the overall rates from the gender-specific rates shown in the figure.) Many of the questions still remain, however.