
Ironheart (Marvel Studios' final Phase 5 project) repeated the MCU's biggest post-credits scene mistake, which could hurt the franchise's future. Including a post-credits scene has been a staple of the MCU since Phase 1 to set up future projects and stories. New characters and stories are usually introduced in these after-credits sequences, but there has been an ongoing problem with this strategy because of the abundance of MCU projects (which led to unresolved storylines for quite a while).
While some of the sequences are intended to be fun (like Iron Man 3's stinger featuring a conversation between Tony Stark and Bruce Banner and The Avengers' iconic shawarma scene), movies and Disney+ shows use more post-credits scenes to tease what lies ahead, but the problem still exists that there is no clear resolution to most of these storylines. Although Thunderbolts* (The New Avengers) made history by featuring a scene directly from Avengers: Doomsday, the unresolved dilemma behind the MCU's post-credits scenes is still a larger problem, and the latest MCU project, Ironheart, proved that.
Ironheart repeated the MCU post-credits problem by setting up a new project that could be years from being released. In the post-credits scene, Parker Robbins (after being defeated by Riri Williams) went to see Zelma Stanton to seek her assistance in connecting him to a "heavy-duty magic" or a "Supreme-like help," indicating that he needs someone like Doctor Strange or Wong so that he could regain his powers.

The conversation between Zelma and Parker appears to set up a project like Strange Academy, where the former hooded villain could join the ranks of other students in Kamar-Taj. However, this post-credits scene sets up a project that isn't even in production or active development, which has been a problem for many post-credits scenes in recent years.
This isn't the first time the MCU has done something like this, as evidenced by several other post-credits scenes featured in Phases 4 and 5.
Ironheart follows the story of Riri Williams as she becomes entangled with a magic-based villain that tests her genius intellect. The series stars Dominique Thorne as the titular hero, Anthony Ramos as Parker Robbins, Regan Aliyah as Zelma Stanton, Sacha Baron Cohen as Mephisto, Alden Ehrenreich as Zeke Stane, and Lyric Ross as Natalie Washington.
The Most Recent MCU Post-Credits Scenes That Have a Similar Setup Problem
Shang-Chi

Shang-Chi and the Legend of the Ten Rings' post-credits scene revealed that the titular hero's sister, Xu Xialing, is rebuilding the Ten Rings organization, essentially setting up the rumored Ten Rings project under director Destin Daniel Cretton. However, it has been almost four years since the setup, and it seemed that the project is nowhere near its release because Cretton is busy with Spider-Man: Brand New Day.
Eternals

Perhaps one of the biggest unresolved storylines in the MCU is the tease at the post-credits scene of Eternals, where Dane Whitman can be seen contemplating whether to take the Ebony Blade before an unseen Blade (voiced by Mahershala Ali) can be heard in the background. Ali's involvement in the scene heavily suggests that this could set up Blade, but the project has been stuck in development hell for a while, and there is no word on when it will be released.
Doctor Strange in the Multiverse of Madness

Another unresolved post-credits scene is the introduction of Clea (Charlize Theron) in Doctor Strange in the Multiverse of Madness' mid-credits scene. The character has yet to appear in some form in any project after that, but the scene heavily implied that it is a setup for Doctor Strange 3 (another unconfirmed project) while other rumors claimed that she will appear alongside Stephen Strange in Avengers: Doomsday.
Thor: Love and Thunder

Thor: Love and Thunder's post-credits scene introduced Hercules (Brett Goldstein) in a way that sets up a future clash with Thor in another project. A recent rumor claimed that a spinoff revolving around Hercules could happen sooner rather than later, but no official announcement from Marvel Studios has been made.
Guardians of the Galaxy Vol. 3

Guardians of the Galaxy Vol. 3 ended with Star-Lord returning to Earth to live with his grandfather, with a post-credits promise that the character would return. However, there has been no update about his potential comeback, but many suggest that he will make his highly anticipated return in Avengers: Doomsday (Read more about the rumored and confirmed cast of Avengers: Doomsday).