As far as I remember the FP5 was “removed from the easy installer” because it caused issues. So is there anywhere in the e/OS forum a hint that this is forever?
Have a look here and maybe check IodeOS as option as well.
General comment: owning a FP5 does not mean you know how to flash Custom ROMs or you dont need to own a FP5 when you are familiar and comfortable in general to flash a Custom ROM.