Warning: SPOILERS for The Falcon and the Winter Soldier Episode 5 - “Truth.”
Iron Man was always the The Falcon and the Winter Soldier. Granted, it made total sense that Tony would serve in that role originally. He was not only a genius inventor, he was also a skilled craftsman, and perhaps most importantly, had enough money to purchase absolutely any material or machine he needed to make an idea come to life. He was even able to invent a method of traveling through time.
Unfortunately, Tony isn't around anymore, after having sacrificed his own life to stop Thanos from wiping out the entire living population of the universe at the end of Avengers: Endgame. He left behind daughter Morgan and wife Pepper Potts, as well as many Avengers colleagues who looked to him as a friend and/or mentor. As sad as that is though, life goes on, and so it does in the MCU too. Superheroes still need gear and high-tech suits and, without Tony in the lab, a new source needed to be found.
That's where it seems Wakanda will come in. Under the reign of King T'Challa, Wakanda has become much freer in sharing its advanced technological capabilities, and other MCU heroes are reaping the benefits, including Bucky Barnes. It appears part of T'Challa's plan to open Wakanda to the world includes supplying certain heroes with upgrades and advanced technology.
Wakanda Replaced Iron Man As The MCU's Tech Source
An early hint at the coming transition to Wakanda, likely lead by head researcher Shuri, as being the lead supplier of superhero tech in the MCU came during Vibranium arm, but they also furnished Captain America with a replacement shield for the first battle against Thanos, and came close to finding a way for Vision to survive without the Mind Stone. With The Falcon and the Winter Soldier, the position of Wakanda as the masters of advanced technology seems to be solidified.
It hasn't yet been revealed what exactly Bucky commissioned Wakanda to create for Sam Wilson in The Falcon and the Winter Soldier, but the most logical guess is a new Captain America suit, one likely made of Vibranium in the same way that Black Panther's Shuri-designed suits are. Since Sam doesn't have superpowers, the ability to absorb and send back kinetic energy from attacks could prove vital to upping his odds against super soldier foes like Karli Morgenthau and John Walker. The gift from Wakanda could also be new, Captain America-themed Falcon wings, but it's possible Sam's original wings being broken was intended to mark Falcon's end and the beginning of Sam as Captain America in the MCU. Either way, should he ever want new wings, he knows what country to call.