i personally prefer top!hua cheng and bottom!xie lian but i’ve read bottom!hua cheng fics too and if it’s in character then it’s great, no problem! but you don’t need to change who they are to fit whatever your erotic preference is for them! i don’t deny that there are people who mischaracterize xie lian as an uwu frail baby uwu or draw/write him as such, but any time it happens people immediately get on the people who do that. and if people really want to write them switching or hua cheng being pampered/taken care of/bottoming, they don’t need to change hua cheng’s whole fucking appearance and personality and canon characterization to do so.
xie lian isn’t weak or effeminate or a baby if he’s bottoming. it’s not as if portraying xie lian as a bottom would be “unwoke” because he’s always protecting, carrying, and taking care of people, and the whole point of how gorgeous hua/lian is comes from the fact that hua cheng was once saved and protected by xie lian and quite literally carried by him, that xie lian was his savior, and now hua cheng is strong and powerful enough to take care of xie lian and xie lian finally has someone he can be vulnerable in front of, someone who actually wants to prioritize HIM and take care of him, when for the past 800 years it’s always been xie lian bleeding and sweating and sacrificing and dying for other people.
so i think the book itself is inherently subversive because the assigned “shou” is actually: older, he’s physically stronger, he is a GOD (and hua cheng is his devotee), and he’s actually a crown prince (and hua cheng was once one of his subjects). but it doesn’t mean that xie lian is written as a baby or as weak, in fact he’s actually stronger than hua cheng. in canon, hua cheng is described as 11 cm taller than xie lian, he is muscled and elegant and xie lian is VERY VERY horny over his body, and xie lian is described as beautiful and ethereal. they force their western gendered norms onto hua/lian because they think “xie lian is a martial god = xie lian has to perform hypermasculinity as dictated by western standards bc i as a westerner can’t fathom a martial god being pretty and ethereal and on the receiving end”. moreover, there is NOTHING WRONG WITH XIE LIAN BOTTOMING, LOL. it’s totally fine if people want to reverse/switch that, but they could do that while making them stay in character. he’s also the assigned “shou” aka “bottom”, and hua cheng is the assigned “gong” aka ‘top”. In the books, yes, xie lian is very strong.