I´ve done a quick comparison tonight.
When paired with Audiosense T800 I definitely prefer the 9038s (g2), because it has noticeably tighter and deeper bass.
R5 plays much smoother and its bass is just slower. It lacks the rumble and proper kick. I´m a sucker for well extended textured bass (planar lover) and even though I wouldn´t say bass is the most important spectrum, I notice "problems" with bass first.
The thing that R5 does best for me is its ability to pushes the stage in front of you, almost crossfeed-like (I never used crosfeed). That is really nice experience, mainly when listening to vocals, however stage is obviously less wide because of this forward shift.
9038S is more dynamic with more microdetail with overall more open presentation. I can imagine if one paired R5 with something like ER4S, it would probably be better match, but can´t say as I don´t have any dry sounding iems right now.
The problem for me with 9038S is that you just can´t wear it easily in your pocket connected to the phone.
Gosh I wish there was a cable like Shanling L2, but with USB-C on both sides. The life would be much easier. Please, if anyone knows where to get one, let me know. (maybe custom?)