The askubuntu link in Swarf's post#5 states it is fixed in kernel 6.9.
According to this post: NVram Locked (Zorin not found in efibootmgr) - #14 by AZorin
Z17.2 will get kernel 6.11 in next 2 months ahead of the Z17.3 release.
Maybe @Gargamel can find another distro with kernel >6.9, then come back to ZorinOS again after that time.