For me, the main appeal of FranXX was the relationship between the two leads, and how they both grow as a result of the bond between them (hence the Jian Bird motif).
Pretty much this, though...
Funnily enough, it was when Mitsuru and Kokoro got more focus over Hiro and Zero Two in the second half that I felt ended up being one of the crippling flaws of said half, along with plot points being flown through without proper set-up or utilization, along with things happening without enough foreshadowing.
... I was honestly more interested on the Mitsuru and Kokoro dynamic and how far they went to stop any potential for natural breeding.
The "fanbase" lost its shit because the anime dare to announce that male and female bonding is the norm, and that the difference genres are distinct, no joke. Already in 2018 trannies seethed and malded about it. The show in the end is very mid and centred primarily of the main duo relationship and the children gaining individually, rather than them all being child soldiers (which to be fair, is just as overused plot element). Biggest issue is the show upping the pacing near the end, but it's not like you miss anything important.
But the end went totally out of the rails, felt like if the series decided to go from this whole oppressive society and their fucked up gender and breeding dynamics and instead go full Gurren Lagann for the end. I will admit I did like the bitter sweetness of the epilogue.
The manga on the other hand is more straight laced, a lot of the plot threads that kind of get dropped in the series or speedran through (the single digits) get more of a presence in the manga and the whole alien plot is more coherent, but I honestly felt it ended like a fart. Anime at least gave some closure.
The series is still not anything that I would file as groundbreaking, but I've seen worse and I do keep good memories of watching it. Also, Kiss of Death is a banger of an OP
On other topics. I follow a bunch of manga weekly from the Shueisha site and I'm amazed by how far Jujutsu Kaisen and Boku No Hero have fallen, and for completely opposite reasons. Jujutsu seems like the author is desperate to finish the series as fast as possible ever since the middle of the weird battle royale arc. Boku on the other hand is dragging everything to a crawls pace (and shat on the whole premise of the series with Iron Might). Monster #8 started very strong but I'm growing colder as time goes on with it. Spy X Family I've just accepted that the "main plot" takes a backseat a lot of the time and I'm enjoying the more slice of life parts of it. Blooming Love and You and I are Polar Opposites are basically concentrated sugar, but have relationships that get very quickly to the "dating" stage which is something I find very rare in romance manga and are a nice distraction.
But as of now my highlights of the week (outside of OP and Chainsaw, though the latter has been kind of meh for a while) are Sakamoto Days (fantastic action scenes and pretty fun, also feels like it isn't aiming for too high of a chapter count), Undead Unluck (started incredibly lame, then hit it's stride but it's been constant fire since it's "time skip"), Make the Exorcist Fall in Love (the drawing takes a while to get used to since it's one of those art styles where everyone looks like a kid..., but it has had some of the most fucked up visuals I've seen in any shounen jump manga and I'm proper intrigued), Magilumiere (magical girls but it's actually office jobs, it sounds retarded but I'm pretty damn engaged) and have some hopes for Kindergarten Wars (I'd file this as a gag manga with some moments of gravitas, has given me a good few chuckles.).