The problem with powered armor is that it is often approached backwards when compared to real design principles. Instead of finding a problem that is best solved with powered armor, most approaches invent the armor first and then try to justify why it is useful.
Most of the time, the problem solved by powered armor is probably better solved by either vehicles or conventional infantry. The value of vehicles is obvious, that they can give mobility, armor, and firepower vastly greater than anything soldiers can carry directly. Infantry by contrast generally offer a degree of stealth and a low logistics cost. Powered armor seems to be in a neither fish nor fowl category, in which it has a similar logistics cost to vehicles but without the same mobility, firepower or survivability as regular vehicles. It also does very little to increase the effective range that a soldier can control.
Even in cases like fighting within a building, as long as soldiers aren't that worried about damaging the environment armored suits would not be that hard to destroy with modern and especially future weapons, and given the costs involved they would be hard to support logistically in the numbers required to be effective at clearing buildings in any major operation. What is also likely more effective than powered armor is the use of fairly cheap expendable drones rather than risking a person even if that person wears armor.
The only real obvious case that justifies the use of powered armor as opposed to something else is in a somewhat confined environment in which weapons and numbers are somewhat limited. One of the few situations that applies here is that of spacecraft, as weapons have to be somewhat limited to avoid breaching the hull of the spacecraft. This means that armor could easily be made in a small enough package to be resistant to most practical ground weapons that someone would be willing to use onboard a spacecraft or space station.
So basically Bobbie Draper in The Expanse is the only good justified use of powered armor given the situation. Another thing that helps in that setting is that they apparently don't trust automation all that much, as there is a similar lack of automation on spacecraft. We've never seen a ship fly without a pilot either, so it stands to reason that we don't see automated combat drones due to a similar lack of trust.
Are there any good earthbound scenarios that qualify as a problem that would be easier to solve with powered armor than the alternative? I'm assuming a tech base mostly similar to The Expanse.