The Strength stat determines not the actual strength, but the ability to control said strength, and apply exactly the required amounts of it. You can have the "strongness" be determined by the actual physical condition of the character, separate from the stat. That way you can have illogical things like switching to a robot or synthflesh body lowering your strength - your body is stronger, but you don't know how to control that strength. The loss of stats on death can be explained by this as well.
Dexterity is the same way. Your body's dexterity is a fixed parameter - it's determined by your body mass versus your strength. Knowing how to use your strength to get your body mass to move with the speed and precision you need to, is what the dexterity stat can be about.
Then you could have things like Battlesuits and exosuits affect these stats as well - unless you wear them constantly for long periods of time, your strength and dexterity while in them is reduced. Battlesuit and exosuit/exoskeleton control could be a separate "skill" thing, and at default levels anytime you're in a power assist device of some kind, your physical stats are back at zero, or whatever the starting number will be.
Or you just limit the max bonus one can get from physical stats to +1, indicating the difference between a novice and experienced/trained people. Anything further needs to come from suit/body. And say that every time a person gets a new suit/body, that person will spend whatever time needed of-screen to get to the equivalent skill level with his or her new thing. It already doesn't make sense one can't increase skills 'n stats through (VR)training, but that as well is needed for the game to run well.
I'd go for the system that's as simple as possible without being
too unrealistic. We can probably explain away in whatever direction we need, so practical use (and thus also ease for gm) should have preference over being realistic in this particular case, as far as I'm concerned.