not an expert, but the fictional part isn’t the suit, it’s the miniaturized high energy production courtesy of stark building it in a cave from scraps.
we have mech suits. we have flight helmets with sophisticated Ai and we have privatized versions of personal assistants.
we have several pieces but we lack the power.
Yep, energy density of materials we can be in close proximity to without getting super-cancer is the bottkeneck.
In terms of actually building something close to the completeness of an Iron Man suit? No.
A) We don’t have powerful / dense enough energy sources. Ironman is powered by a fictional Arc reactor because we have no power source that small that can produce that much power.
B) We don’t have any quiet forms of airborne propulsion. You kind of hear Ironman’s jets sometimes, but not really, and in reality all our jets / fans that can produce enough thrust to lift a person are way louder.
C) Any material strong enough to actually be protective and stop bullets will also way a ton, making flight even more difficult.
D) In reality an Ironman suit wouldn’t be able to stop you from killing yourself through concussions whenever you crashed or hit anything.
That being said, there is a company building jetpacks: https://www.youtube.com/watch?v=suHOLFhbwsM
This guy built a DIY jetpack with arm boosters that fly to you: https://www.youtube.com/watch?v=vSGaCew0xh8
And Adam Savage built a bulletproof Ironman suit out of titanium: https://www.youtube.com/watch?v=zC8go7wE6VU
C is probably closest to reality with light weight ceramics and so on. Though still very very far away from actual reality.
They did also combine it with A to get it to fly, but I would argue that it’s still pretty wildly far away from what we would think of as an Ironman suit: https://www.youtube.com/watch?v=U1wEO-pHizQ&t=24s
Closer than what? In the past? Yes, of course. We’ll always be closer, unless there is some cataclysmic event that causes us to lose knowledge and regress.
You may find this SFIA video interesting.