I think straight to SRS is the more common path (at least with people I know IRL), and that makes sense for lots of reasons.

Orchi before SRS made sense for me for a few reasons:

• my SRS surgeon could do the orchi for me, it was convenient and lined up easily (as opposed to being a completely separate surgeon that I would have to coordinate with my SRS surgeon)
• I had never found a fully perfect way to adequately suppress my testosterone without getting a bit moody from too much estrogen on monotherapy and anti-androgens didn’t work well for me (bicalutamide never seemed to help my biochemical dysphoria, maybe because it doesn’t act much on the central nervous system, like the brain), it was hard to balance my hormones and I seemed to be so sensitive to the testosterone that even a small amount led to things like having days of depressive symptoms, making my life a bit unpredictable and my mood unreliable - so an orchi would essentially guarantee mood stability and better executive functioning, which I reasoned would help me plan and make SRS happen successfully (as well as everything else in my life)
• I felt 100% certain I wanted an orchi when I socially transitioned, there was no (legitimate / actual) doubt in my mind that it was right for me, and I’ve dreamed even of being a eunuch since I was a teenager before I realized I might be trans; when I first socially transitioned I thought I might not even get SRS at all, it was really unclear to me at the time (though now I feel certain I want / need a vaginoplasty).
• because of the U.S. elections and because I live in one of the most transphobic states in the U.S., it’s unclear what will happen after January, but getting my orchi in before the change in power in the U.S. meant it would be much harder to force me to detransition - not having testes gives me a sense of security in an unstable political climate
• orchi is out-patient, relatively easy, low complication, requires no hair removal, and so much cheaper than SRS so it is much easier to achieve with life-long guarantee of female levels of testosterone, improved estrogenization, and no need to take anti-androgens

Some of these are fairly personal reasons, so I don’t think it’s an obvious choice or anything. I also found talking through orchi vs SRS with my therapist fairly effective, she hit me with a question that clarified things for me: “How would I feel living the rest of my life with male genitals?” I realized that would be horrible for me, I want to be a woman in every way, and male genitals definitely make me feel like an imposter. Of course genitals don’t make the gender or anything, but I realized I felt a certain way and that in conjunction with lots of other evidence, SRS increasingly made sense for me.