Acronis true image 2021 not compatible with Windows 10?

I wanted to upgrade my PC from Win10 to Win 11 eventually (this summer) but I just saw that my Acronis True Image 2021 is not supported by Acronis and is not necessarily compatible with Win 11.
It is replaced by Acronis Office Protect essential which works with an annual subscription that is far too expensive to make a backup of the system partition and my files regularly (50 euros/year, the price I paid for the ACTI 2021 license!).
 
I'm a little disgusted.
Has anyone used ACTI 2017 to 2021 restore successfully under win 11?
 
Do you know a serious free alternative to acronis True Image to regularly backup (and restore in case of crash) my system partition and backup/restore my important files?