Maybe someone should design and sell a "drivekeeper" that you can plug all your backup SSD's into and it will power them up on a time table and do whatever is necessary to cause them to maintain integrity. Could be something like a Raspberry Pi with a many-port USB hub, or with a PCB with a bunch of connectors the raw drives can plug into. Could maybe even give a warning if a drive is degrading. Possibly it could be a small device with a simple MCU and a battery that you snap directly onto the SSD's connector?