No, not necessarily.
You could use the same. Just make sure to NOT format it when you install EnOS
Normally you don’t have to resize it. The installer should just detect it and install EnOS’ bootloader in a separate directory side by side that of Windows.
However if you want to effectively isolate the ESP partitions for each system, then you could create a 300 MiB FAT32 partition. You chose the manual install in the installer and mount this partition at /boot/efi and flag it as boot.
Further reading:
https://discovery.endeavouros.com/installation/calamares-installer-tips/2021/03/