This document will guide you how to have 50 ring slots.

First, find the config folder in your .Minecraft folder.
(If you have version isolation enabled,Go to .minecraft → versions → [name of the version you are playing] → config)

Find the file curios-common.toml,Then you can start modifying.

Find "id=ring;size=",Change the number after the equal sign to the number you want, such as 50.

Finally, don’t forget to check the game after the modification is completed.