Inspired by a post by Matipereia. This shows the longest wait between MCU sequels in the timeline.
Guardians of the Galaxy 2 and Guardians of the Galaxy 3 2014- 2026 (12 years)
2 - Doctor Strange 1 and Doctor Strange 2 2016-2024 (8 years)
3 - Black Panther 1 and Black Panther 2 (2016-2025) 9 years
4 - Thor 3 and Thor 4 (2017-2024) 7 years
5 - Ant-Man 2 and Ant-Man 3 (2018-2025) 7 years
6 - Thor 2 and Thor 3 (2013-2017) 4 years
7 - The Avengers 1 and The Avengers 2 (2012-2015) 3 years
8 - Iron Man 2 and Iron Man 3 (2009-2012) 3 years
10 - Ant-Man 1 and Ant-Man 2 (2015-2018) 2 years
11 - Guardians of the Galaxy 1 and Guardians of the Galaxy 2 (2014-2014) 3 months
12 - Captain America 1 and Captain America 2 (1940s-2014) 70 years
13 - Thor 1 and Thor 2 (2009-2013) 4 years
14 - Spider-Man Far from Home and Spider-Man No Way Home (2024-2024) 6 months
15 - Captain America 2 and Captain America 3 (2014-2016) 2 years
16 - Iron Man 1 and Iron Man (2008-2009) 1 year
17 - Spider-Man Homecoming and Spider-Man Far from Home (2016-2024) 8 years
18 - The Avengers 3 and The Avengers 4 (2018-2023) 5 years
Heres the biggest gap to smallest
Captain America 1-2 70 years
Guardians 2 and 3 12 years
Black Panther 1 and 2- 9 years
Spiderman 1-2 8 years
Doctor Strange 1-2 7 1/2 years
Ant man 2-3 7 Years
Thor 3 and 4- 6 1/2 years
Infinity war and Endgame- 5 years
Thor 1 and 2- 4 years
Thor 2 and 3- 4 years
Iron man 2 and 3- 3 years
Captain America 2 and 3- 2 years
Iron man 1 and 2- 1 year
Spider-Man 2 and 3- 6 months (for the main events of the movie)
Guardians 2 and 3- 3 months
Let me know if I made any mistakes