This might be going off on a tangent but does the "suit" have to be a suit at all it could could be something similar to the Klyntar aka"symbiotes" from Marvel, where the "suits" are an amorphous mass of cells and/or nanites that act similarly to an amoeba yet they are sentient, where they bond to the host permanently or have some semi-permanence to the bond where the "suits" could then be inside the human host and give them advanced abilities such as rapid healing, body weaponization, enhanced intelligence, and reflexes, or other such abilities. In return, the host must consume specialized foods and materials or instead they have to consume different animals or genetic material to gain these abilities after the bonding process as well as consume more food than was otherwise necessary to sustain the host for a day before said process. Said host could also have the ability to rapidly evolve in response to certain stimuli or circumstances. 113
These "evolutions" could be performed in a lab like controlled environment to increase the likelihood of these "evolutions" taking place and/or these evolutions could happen in any environment at any time taking place randomly with the increased likelihood of these evolutions being beneficial but unknown in the scientific sense that the creators didn't realize that they could or could not evolve in that way, thus creating the possibility for endless rapid self-evolution, this could lead to extraordinarily long or near infinite life spans.
The symbiotes could also innately be only semi-sentient or sentient to a degree in that they understand that the one they bond with will be the one they die with or that they develop their personality with. The "suits" in a sense would be in a perfect symbiotic relationship where the "suits" and the host are in a permanent bond that couldn't be broken but would cause extreme often irreparable emotional harm not just to the host but also to the "suit". The "suits" after a while develop their own intelligence based on what would be the most beneficial for the host such as <PERSON> and <PERSON> (Inheritance cycle) and John-117's "Cortana" AI even though one example is dragon and rider telepathic bond and the other is a relationship between Master Chief and his AI the same principle applies it would cause irreparable emotional harm to kill one or the other.
The suit in a sense would become the partner of the host they could think individually and as one with the host even as each has a full range of emotions they can experience each other's. 113