Yeah that's the thing, I think. Most of what we think of as isolating suits IRL need to supply oxygen/remove CO2 from any circulating air and often are designed for situations where they need to be pressurized, none of which AZ needs. And wetsuits which mostly just insulate are reasonably flexible, as someone who had a bestie who owned a few of them because he liked SCUBA diving.
And so yeah I don't put it past Tachyon to successfully design a materal that is basically mega-insulating but still has the general properties of wetsuit material. Especially since considering how often the guy has to be in it and has to be able to fight in it, it needs to be at least halfway flexible and comfortable.
Granted, if I had my druthers, I still would have preferred a similar pose but just with AZ as himself in his cryo chamber.