so this is an interesting question but i want to disclaim that my ability to really discuss the nitty-gritty of music beyond "what sounds good to the neurons in my brain that solidified at age 15" is pretty limited

I think it's kind of an argument of how cohesive you think they SHOULD be and i have always erred on the side of liking it when they don't sound like each other.

so, like, if you take all of the songs that have multiple full units on them, you're looking at:
-Rap Guerrilla (the original version)
-Rap Guerrilla Reload
-Rise Up (the anime OP)
-Here We Go (Parasute Vol.2)
-29 Verse

And honestly, I've always felt like Rise Up and Here We Go both have the problem of basically just sounding, through their cohesion, like a BAE song that everyone else gets a verse on.
This isn't a knock on either of the the songs themselves (I like Here We Go quite a bit, and I actually don't mind Rise Up as a song on its own, I just hate the anime, lol) but i do think that it turns them into kind of a non-diegetic roll call rather than songs that feel grounded in the universe

I have said this before and I'll say it again: except for the group songs (and arguably the collab songs) every song is at least somewhat grounded as being created in-universe, and the groups do not as a whole hang out with and make music with each other. I can't really imagine akan yatsura, visty, amprule, and cozmez all rapping over the same beat outside of the context of a Roll Call Opening Number, you know?

I think the closest to my personal ideal that the franchise has ever done is the original Rap Guerrilla, because those four verses do sound like they were made by different people while also fitting together pretty well... but by contrast, Rap Guerrilla Reload's back half has always sounded to me like every member of a group project did their parts of the project separately and they're trying to staple them together morning-of. I do like it, don't get me wrong, but it's been hard to escape the knowledge that they are four new verses tacked onto a pre-existing song (and the VISTY > AMPRULE and 1Nm8 > GokuLuck handoffs are both lowkey trainwrecks imo). But that said, I don't think that (for example, and im just choosing two verses i really like so I'm not picking on anything) the TCW and cozmez verses on Rap Guerrilla are thaaaat much more dissimilar than any two group's verses on 29Verse if you actually listen to them.. Certainly the TCW verse vs the AMPRULE verse is just as big a gap as between any two verses in 29 Verse, and because 29 Verse was written with nine groups in mind instead of four-then-nine, i personally think it works a lot better.
so like, in theory, rap guerrilla reload is my personal ideal in that all of the parts ARE very disparate while having their throughlines, but it's been a little held back by the fact that it is a post-hoc addition to an extant song

so what i guess I mean is:
to me, 29 verse is kind of what I'm looking for in a big 9-unit song for this francise-- everyone is matching the same beat (it does in fact keep to 132 BPM the entire time; sync up a metronome to keep track alongside and it's deeply satisfying if you're weird like me WWW) without sounding the same, which is kind of the point when the entire point of the song (and the story arc) is that the groups are all very different, coming from different backgrounds, and have different sounds