interesting thing i've noticed with they/them: i vary between using "themself" or "themselves" varies, but for the most part, i don't really know what my internal criteria for whether to pick one or the other is. however, i recently realised that one of the factors is whether the sentence includes "they".

for example, i'll probably say "they found themselves on the map" - "they found themself on the map" feels off in a way i can't put my finger on. in contrast, "morgan found themself on the map" sounds more natural to me than "morgan found themselves on the map".