Exway's Flex Pro is a commuter-friendly board with smart battery management, and "sleep mode" problems often revolve around the BMS, firmware behavior, or a battery that has been stored too long at an unfavorable charge level. If the fix is a known battery or firmware remedy, replacement of the battery pack (or BMS service) can be justified when it restores reliable wake/charge behavior-especially if motors, deck, and ESC are otherwise solid.
Compare battery replacement costs and any diagnostic labor to the repair threshold. If the board is relatively new, repair is usually sensible; a dead battery shouldn't force full board replacement unless parts are unavailable.
Replacement becomes more attractive when the battery issue is paired with water exposure, repeated ESC faults, or severe capacity loss that suggests the pack is at end-of-life anyway. Also consider safe storage practices going forward (moderate charge, cool temperature), since battery care strongly influences total ownership cost.