Marvel's Agents of S.H.I.E.L.D. is using technology that's up to 10 years ahead of Tony Stark. The foremost hero of the MCU, at first glance Tony Stark is an unparalleled genius. He's pioneered miniaturized Arc Reactors, developed nanotech, discovered new elements, cracked thermonuclear astrophysics overnight, and in Avengers: Endgame he worked out time travel and quantum mechanics with apparent ease. Marvel may insist that Shuri is actually smarter than Stark, but there's no way she's as accomplished.
The bulk of Avengers: Endgame is set in 2023, and over the last five years Tony Stark has clearly continued to improve the Iron Man armor. The film saw him don the Mark 85, but sadly it didn't really present many opportunities to showcase the Mark 85's talents. The most notable features were a cloak, a "Nano Lightning Refocuser" to combine with Thor's powers, and - most curiously - a photon shield that protected Stark during Thanos' attack. This photon shield actually subtly hints that, in contrast to viewers' expectations, Stark probably doesn't have access to the most advanced tech on the planet. That distinction goes to S.H.I.E.L.D., whose science may be up to a decade ahead of Stark's.
As impressive as Tony Stark's photon shield may be, it's actually nothing new; S.H.I.E.L.D. cracked the same tech back in Agents of S.H.I.E.L.D. season 3. Phil Coulson had lost his left hand after being exposed to the poisonous substance Terrigen, and Fitz had developed a cybernetic replacement. As the season went on, Fitz began to add new functionality - most notably a photon shield. That means Coulson was using this kind of tech a full eight years before Tony Stark.
In fact, this isn't the only evidence that S.H.I.E.L.D. is ahead of the game when it comes to advanced tech. In part that's because the S.H.I.E.L.D. team tend to collect and study alien technology, learning key lessons from it and frequently reverse-engineering it. In part, though, it's also because they tend to put together a team of brilliant scientists, and this kind of teamwork naturally produces better results than one maverick inventor. Take the example of the Life Model Decoy program that created lifelike androids, which was name-dropped in The Avengers; according to Agents of S.H.I.E.L.D. season 4, Stark was part of an initial failed project, but Doctor Radcliffe's genius eventually unlocked it (albeit to disastrous effect).
The last two seasons have gone one step further, demonstrating just how advanced S.H.I.E.L.D. really is. In season 5, S.H.I.E.L.D. encountered an alien Confederacy who possessed remarkable matter-transportation technology. By season 6, S.H.I.E.L.D. had successfully reverse-engineered this tech, and had succeeded in creating Earth's first intergalactic spacecraft. It's currently unclear how this works; it appears to be a different form of transport to that displayed in the Guardians of the Galaxy films, so may well operate on principles Tony Stark hasn't even encountered. This accomplishment is all the more remarkable given S.H.I.E.L.D. was actually missing their top scientist, Fitz, during this period; in fact, they've taken to space for the purpose of tracking him down.
Looking back through the last few seasons of Agents of S.H.I.E.L.D., it's clear that S.H.I.E.L.D. remain several years ahead of Tony Stark - perhaps even a decade or more.