To me, Yas and Yama being capable of holding their ground against 4 of his personal beasts tells as much as 20th Floor Baam being able to push Mule Love around and withstand his attacks (even though the latter's casual jab nearly scored 100x higher than Baam's Floral Butterfly Piercing Technique in the Quant Punching Machine and by later showings of Rankers, there was obviously an extremely bottomless gap between the two).
Or 21st Floor Baam being capable of withstanding a legendary technique from Urek (Supreme King's Scorching Fist of Death) when his 1% finger can pulverize High Rankers of Karaka's calibre.
Or Zahard being unable to kill the members of the Hidden Grove with multiple Golden Needles of Mystery Island when judging by Khun Hynd Luch's standing, none of the people there bar Khel Hellam should have exceeded the level of an average High Ranker (Division Commander) and probably were well below that (Toro had his blood boiling by the thought of facing a random Ranker at the Walls of Coexistence and the random Ranker could clash evenly with him for some moments).
All of these moments show that characters in this series can potentially hold back multiple orders of magnitude beneath 1% of their power. Traumerei is just another example of massively holding back IMO. I mean, I think you can see it clearly on him too. He wasn't even paying attention to them. The moment Yas showed his FT, the dude went back to sleep and just in this latest chapter he went from "4 of my personal Shinheuh can't get rid of Yas and Yama" to "I'll eviscerate everyone within the Nest with a single Shinwonryuu", and god knows how much power he still has in reserve. Yas also said that even if 1 million people were to stand there with them, victory would still be impossible (likely hyperbole but it at least shows how much Traumerei is fucking around here, and Yas is perfectly aware of it). Even Baam, who at this point is very likely to stand in a whole different realm of power than Corps Commanders if he uses all of his powers, feels like he could potentially be killed in an instant if he shows the slightest bit of hostility towards him (granted, the dude is not his biggest supporter considering how he said he's clearly still not as strong as his master lol).
IMO, some people are just a bit impatient and sometimes forget SIU is writing a story. The fight between Yas, Yama and Traumerei is something that SIU has been building up for a lot of time now. It would be incredibly anticlimatic if Traumerei were to stand up and instantly eviscerate both with one attack to go back to sleep (even if that's what should realistically happen if he tries just a bit).
I expect those Shinheuh to be far, far beyond Corps Commanders when used appropriately. My guess is that they either have multiple phases that we have yet to see (similar to Dokoko's Windbird), or what's more likely IMO, that Traumerei has yet to reinforce them with Shinsu (or that if he's reinforcing them with Shinsu, it's with an insignificant portion of it). It could perhaps even be a combination of both. Anyways, the dude isn't hyped to be an exceptional Fisherman among the Great Warriors, neither an exceptional Spear-Bearer or Light-Bearer or Scout or Wave Controler. Traumerei's main hype comes from being the strongest Anima in the Tower and Animas fight using their Shinheuh. Considering that and how relevant Shinheuh are to the strongest members of his Family (see Dokoko, the 8th Son Yorari or Pudidy for example who even now is still lamenting his retarded move of not bringing his Eagle Owl in a battle full of top-level High Rankers), the notion that 4 of his main beasts would be unable to fodderize what should be the equivalent of dust to someone of his level is simply nonsensical.
