If you want to watch it, in order of return on time invested
FILM = theatrical movie · SERIES = Disney+ / Netflix show
Tier 1 — the load-bearing fifteen (~33 hours) The Avengers (FILM) → Age of Ultron (FILM) → Civil War (FILM) → Infinity War (FILM) → Endgame (FILM) → Loki S1 (SERIES) → Shang-Chi (FILM) → No Way Home (FILM) → Multiverse of Madness (FILM) → Wakanda Forever (FILM) → Loki S2 (SERIES) → Deadpool & Wolverine (FILM) → Brave New World (FILM) → Thunderbolts* (FILM) → Fantastic Four: First Steps (FILM)
Tier 2 — the texture that makes the above land Winter Soldier (FILM) · Doctor Strange (FILM) · WandaVision (SERIES) · Falcon and the Winter Soldier (SERIES) · Black Widow (FILM) · Hawkeye (SERIES) · Quantumania (FILM) · The Marvels (FILM) · Agatha All Along (SERIES) · VisionQuest (SERIES) · Spider-Man: Brand New Day (FILM)
Tier 3 — the X-Men homework — all FILMS X-Men (2000) · X2 · The Last Stand · Days of Future Past · Logan · Deadpool 1 & 2
Tier 4 — not required FILMS: Iron Man 1–3 · Thor 1–3 · First Avenger · Guardians 1–3 · Ant-Man 1–2 · Captain Marvel · Eternals SERIES: Ms. Marvel · She-Hulk · Secret Invasion · Echo · Ironheart · Moon Knight · Wonder Man
Tier 5 — the street level — all SERIES Daredevil S1–3 · Jessica Jones S1 · The Punisher S1–2 · Born Again S1–2
The three watch-order traps
1. Don't watch Loki Seasons 1 and 2 back to back on a first pass. They're separated by two years and by Quantumania, and Victor Timely's appearance in Season 2 reads differently after it.
2. Hawkeye's finale aired five days after No Way Home opened. Watch episodes 1–5, then No Way Home, then the finale.
3. Black Widow's post-credits scene takes place years after the rest of the film. If you watch it chronologically, skip that scene and come back to it at Hawkeye.