You can read everything on the difference between the new Fitbit Versa and Fitbit Sense 2 here.
Fitbit Versa 4 Review: Sense 2 Lite - Tech Advisor
Buy Fitbit? - Coolblue - Before 23:59, delivered tomorrow
Fitbit Sense 2 vs Versa 4: What's the difference?
Fitbit Versa 4 review: the good, the bad, the ugly
Fitbit Sense 2 vs Fitbit Versa 4: Which is Better?
The Fitbit Sense 2 and Versa 4 now support a single third-party app
Fitbit Sense 2 & Versa 4 Review: In the shadow of the Pixel Watch
Fitbit Sense 2 vs Versa 4: What's the difference?
Advanced health & fitness smartwatch