I have been using Clonzilla for years and it never let me down.
I run it from an live USB stick on my Desktop PC. It has some learning curve but you will find a lot of tutorials online. Running "disk to local image" to backup and "local image to disk" to restore with the defaults should be enough as a start.
As long as the source hardware from where you make the backup and the target restore hardware are the same make and model it should go smooth (i.e. Rpi4 -> Rpi4, SD-card make and model can differ but obviously the size of the target should be same as source or larger).
I assume you only use the SD card for RetroPie and not a mix of SD-card and SSD drive for RetroPie.
Do you use a SD-Card reader via USB in your Desktop PC or is the SD card directly put into the PC's SD-card reader? (I am asking as I have seen USB SD-Card readers failing).