It’s been my experience that SD cards are almost always what causes a failure on a SBC. Given the cost of the screens, i’d probably choose something that could boot off nvme storage. Or at least tape a new, configured SD card to the case of the SBC for when this inevitably happens.
Using an actual hard drive for an embedded system like this would be a failure in and of itself.
Unless it literally has to store several hours’ worth of HD video content, no reason the entire system couldn’t fit on an SD card.
An SD card is MUCH less reliable than a good hdd unless it’s read only.
It’s been my experience that SD cards are almost always what causes a failure on a SBC. Given the cost of the screens, i’d probably choose something that could boot off nvme storage. Or at least tape a new, configured SD card to the case of the SBC for when this inevitably happens.