Scenario: 


- you are using Microsoft OneDrive 

- you are using known folder redirection also known as "OneDrive known folder move", 

- you have setup Windows 10/11 Storage Sense for OneDrive to remove obsolete files from your local SSD / HDD

- you have a slow internet connection or metered connection (optional) 

- you do not regularly startup Humankind

- you have played a lot of Humandkind (aka have many savegames)


make sure that you subscribe the folder to prevent Storage Sense cleaning up the folder, which invokes that it needs to download it again at game startup.
Alternatively use the cloud save option in Humankind if you want to rely on their servers instead of OneDrive instead.

How-To:
Windows Explorer > OneDrive > Documents > Humankind > right click Savegames > Always keep on this device

In this case can combine using benefits of edge and secure tech, with convenience. Hope it helps.
If this helped you, thanks for comment of appreciation, and / or your upvote on the top right. Amplitude for consideration in their FAQ / guides @The-Cat-o-Nine-Tales.