This is a model for the 2021 version of FormFutura cardboard spools and the 2022 differs a little bit but I remixed a version for it also which cand be found here:
FormFutura Cardboard Spool Ring 2022 Version
I used two existing models to create one that perfectly fit my needs.
I recommend printing it with the same material that is on the spool itself for when you are drying the filament not to affect the ring or to choose a material like PET-G or ABS/ASA from the beginning.
The author remixed this model.