Just my gut instincts of Phases here after what we’ve been talking about, if you want some description of my opinion about these and their placement let me know, but this assumes that Spider-Man is still in play, that Chris is staying on as Thor, that Captain America and Iron Man are off the board and finally that the X-Men and Fantastic Four aren’t in play until Phase 5 and finally that the nine release dates we have for MCU films are all Phase 4:

2019

Spider-Man: Far From Home (July)

2020

Black Panther: Wakanda Forever (May)
Doctor Strange: Nightmare (November)

2021

Black Widow (February)
Guardians of the Galaxy Vol 3 (May)
New Avengers: Eternal (November)

2022

Shang-Chi (February)
Spider-Man: Sinister Six (May)
Captain Marvel: Secret Invasion (July)

With Dark Avengers, Thor: Siege, Guardians Of The Galaxy: Annihilation and both X-Men and Fantastic Four stuff in Phase 5. I realise I have missed Ant Man in here of course but it probably depends on how many movies Phase 4 gets slots for.