Each material has some characteristics and benefits that give it better benefits over others. That is why I will always say the same thing, there is no one material better than another.
Mounting a carbon fork on a custom steel frame provides a plus in comfort by providing better absorption of the unevenness of the terrain, but it’s more uncomfortable than a steel fork by providing a more rigid response to the bike’s behavior.
The steel fork will make the bike more comfortable to ride, with more options for adding peripherals (extra bottle cages, for example), but the unevenness of the terrain will not be absorbed as well.
I just got you hooked up, didn’t I? Forget everything, when we talk and see the type of bike you need the choice of fork will come by itself.