How to connect a hard drive to Zyxel Keenetic 4G III?

Question

Hard disks

Hello!
There is a Zyxel Keenetic 4G III router (revision A - black) and a desire to connect a hard drive to it via USB so that it is available on the local network. This model by default can use USB only for modems, but I do not need this functionality. Is there a ready-made solution (firmware) for my router that will help me connect a hard drive?
Of course, I googled, but I did not find a ready-made firmware for this model. If you didn't search well, please direct me.
Thank you!