The Final Fantasy 7 timeline can be convoluted, especially with so many spin-offs, so fans should check out where Crisis Core fits into the story.
Final Fantasy VII Rebirth - Wikipedia
How much time was there between the events of Crisis Core and Final Fantasy VII? - Quora
Crisis Core: Final Fantasy VII Reunion Review - Required Reading - Game Informer
Compilation of Final Fantasy VII - Wikipedia
CRISIS CORE –FINAL FANTASY VII– REUNION Is Available Now
Final Fantasy VII Rebirth's timeline — catch up before the PS5 launch
Timeline: Final Fantasy VII: Page 4
Everything you need to know - The only theory post that explains WHY & HOW there's multiple timelines : r/FFVIIRemake
Crisis Core: Final Fantasy VII - Reunion Review
Crisis Core Reunion's Connection To Final Fantasy VII Remake, Explained