Given that ESP Mounter Pro is no longer actively maintained (last update 2020–2021), consider these safer, more modern alternatives:
ESP Mounter Pro v1.9.1 Download: The Definitive Guide to Managing EFI Partitions on macOS esp mounter pro v1.9.1 download
Right-click the application icon and choose Open to clear initial unsigned developer alerts from macOS. Given that ESP Mounter Pro is no longer