As others have already identified, the most fundamental Achellies Heel of current powered frames, be it hard or soft, is the issue of power supply, specifically, power supply size/weight to endurance ratios.
Personally, other than maybe some logistical handling applications at bases, on ships and maybe large cargo planes, I just cannot see any of the current conceptual powered frames being adapted unless there is a quantum leap in portable power supply and storage technology.
Maybe the tech insiders know something I don't, which is probably extremely likely tbh, but ruling out such a fundamental breakthrough, all the current conceptual designs are pretty much all dead ends at the conceptual level as far as frontline combat operations are concerned.
Rather than present the customer(militarise and maybe PMCs) with a produce that is useful, they are presenting them with the best the can manage at an idealised fantasy system that simply cannot be made with current or even medium term technology.
It would be like LockMart going to the USAF with a space fighter proposal and a sales pitch ripped off of a Hollywood script without engines able to get the thing into space anywhere on the horrizon.
Ultimately, in 30 or 40 years, once all the key component parts have been developed, these designs may find an application, but with current technology, it just isn't going to work or be worth while when you consider the cost to performance ratios.
Governments will continue to fund such programmes as almost a tax to stay in the game, but don't expect any to be fielded in meaningful numbers without the aforementioned power supply break through.
If I was to present a pitch for a system that might be front line operationally fieldable within the next 10-15 years, instead of trying to develop a man sized independent system, I would cheat and relax the requirement a little.
My proposal would be the a Centaur design. I would take the robotic maul design currently being field tested by the US marines and mate that with a powered hardshell exo armour to update cavalry to the battlefield of the 21st century.
The robotic maul would provide enough internal volume to mount a big enough power source to allow for realistic operational endurance.
Removing the requirement to be man shaped and sized, the legs of the maul could be designed to offer far higher speeds than a humanoid frame could reasonably manage, all without unduly taxing the wearer. In that regard, you can go from the bipedal design of the ostrich, to the more conventional 4 legged mammalian chassis, all the way to the 8 legged arachnid frame. Basically whatever suits your need.
The mauls could be used by themselves as is for special forces to move rapidly in terrain unsuitable to even the most robust of wheeled and trackedh vehicles, but I would exploit the enhanced carrying capacity to mount a human in a powered, fully or partially enclosed armoured suit.
The suit would normally be plugged into the maul and rely on that as its primary power supply, so does not need to be able to last days out in the field under its own power, making it far more attainable with current or near current level of technology.
Asside from the significant additional protection it offers over conventional plate and Kevlar armour, it will also allow the user to carry and wield significantly heavier and powerful weapons than even the strongest human could realistically carry and use unaided.
The protection level, firepower and endurance of the suit could all be augmented by the maul, so you can mount a heavy ballistic shield on the maul in front of the rider that can stand up to direct and repeated hits from 50 cal or even 20mm rounds so the suit itself does not need that level of protection to reduce the weight of the suit. You can also have easy to detach mounts on the maul so the heavy weapons of the suit would normally only need to be swung around to be aimed and fired rather be wielded like a conventional rifle, reducing the power consumption even in combat.
The suits would be easily detachable form the mauls as easily as a rider might dismount from a horse (or even easier as the maul can be specially designed for rapid dismount) so the rider has the option to move out on foot from tight spaces or stealth or any other reason.
For reliability, you can use an old calvaryman's trick of taking more mounts than riders. Since the mauls would be doing the lion share of the running, they would be the most likely to fail. If one breaks down, the rider can simply ditch it and hop onto a spare.
Those spares could normally be used to carry food, water, ammo and other supplies and equipment, which are either used up during the course of the mission, or could be re-distributed amongst the remaining mauls or even ditched in the event of mount failure. Hell, you can even use one to carry a spare powered suit to give you redundancy there as well if you want.
In combat, the spare mauls can just stay hidden, or even be used as remote controlled or semi-autominous armed drones to help with the attack.
The riders can use their mauls like traditional cavalry from high and run attacks of light cavalry, to the line breakers of heavy cavalry or they can dismount and fight like foot infantry, only with far better protection and firepower.