Hi @MaximeBessou,
Great news, the Auto number abbreviation feature you suggested is now live! 
You can now set abbreviation to Auto in your number format settings. Holistics will dynamically assign the right unit (800, 4.5K, 2.5M, 1.2B) based on each value’s size in the exact same column.
Check out our community post here for more details: [Launched] Auto-abbreviate numbers to K / M / B 
- Product Releases - Holistics Community
Thanks for helping us improve Holistics!