CMAKE_REQUIRE_FIND_PACKAGE_<PackageName> is not really useable in its current state
Currently CMAKE_REQUIRE_FIND_PACKAGE_ makes every find_package
call for PackageName
a requirement.
This doesn't really work well with the examples mentioned in https://cmake.org/cmake/help/latest/command/find_package.html
e.g.
find_package (<PackageName> PATHS paths... NO_DEFAULT_PATH)
find_package (<PackageName>)
or
find_package (<PackageName> CONFIG)
find_package (<PackageName>)
I don't know if it also affects find_package (<PackageName>)
doing an internal call to find_package (<PackageName> CONFIG)
My suggestion would be to make the REQUIRED check at the end of the current list dir instead.
(I mainly see this issue in Qt where I am unable to force the lookup of optional packages)