My perspective is that the biomod controller fits in well with the way other augmentations are handled in the game.
Compared to other game system with cyberware (CP2020 and Shadowrun as two examples), augmentations in Sindome seem extremely limited. In other systems, it is not uncommon for characters to have a dozen modifications if they live long enough.
As a player, I had to recalibrate my expectations of what "being augmented" means for my character. They will never have ALL of the augmentations. They will never even have half of the available augmentations. More than likely a character will end up with a small handful of thoughtfully selected augmentations that suit a specific play style.
The way I have reconciled that and made sense of it in an IC way is that augmentations are invasive. They are major changes to a character's physical body. They might come in the form of nanos that are rewiring the body on a deeply cellular level. Or they might be eyes, or ears that are augmenting existing senses or adding entirely new senses. Or maybe they are something like a flash boost that is putting the central nervous system into overdrive. Or they are biomods that are literally redefining the body to less human and more animal.
A body can only handle so many changes. If a character wants ears and a tail that move around, they are giving up the option of having other types of augmentations. If a character wants a bunch of nanos, they are giving up on having a bunch of cyber. The reverse is also true.
If there is one thing I have learned about Sindome it is that no one character will ever be able to excel at everything. It is not that kind of game. There is a max UE cap. There is PDS that limits augmentations. There is a fatigue system that limits how active a character can be. Navigating around the limits and striking the balance is both art and science. To me, the limits on any one character becoming great at everything is one of the biggest selling points of this game because it forces characters to collaborate and team up with people who capable of doing other things.
I have not seen a single authoritative voice mention that players cannot create biomodded characters. All I have seen is staff saying that there are costs and trade offs to being biomodded. A player is not going to be able to create a flash boosted, cyber eared and eyed, quadruple nano'd cat samurai with moving ears and a tail.
If you want to play a fully functional furry, that's fine. Just accept that there are tradeoffs. Just like anyone else accepts that if they want augmentations A, B & C that they are going to have to give up augmentations Y & Z. It's not that they cannot have Y & Z. They just can't have EVERYTHING.