Keyboard under System Settings should give you options for changing all the modifier keys. I've got Caps Lock modified to be Escape on mine. Though the jokes on me as I just hit ESC all the time and forget about my remapped Caps.

There's similar options on iOS if you use an external keyboard there.

No because Backspace is not considered a modifier key. The available options for Caps Lock are Control, Option, Command, fn, Escape or just disabling the key entirely.

If you have a workflow that involves RDP to Windows, you also basically have to use Karabiner to swap command and control for RDP only in order to maintain sanity of shortcuts between macOS/Windows.

There is a builtin utility for this on Macs with a few ways to configure. This is the commandline arg to remap caps lock to backspace

hidutil property --set '{"UserKeyMapping":[{"HIDKeyboardModifierMappingSrc":0x700000039,"HIDKeyboardModifierMappingDst":0x70000002A}]}'