Then your post asking for HW redundance was a bad move.
It made us victim to the XY problem. Pay more attention next time please.
That being said, go openHABian on a RPi. It has the ZRAM feature to mitigate SD wearout problems. It also has its own backup system that you can and should use to create a spare SD card.
A dedicated system (even if it’s just a RPi) is preferred over units to share functionality with other systems such as a NAS (even if they’re hypervisors).