You can use Advanced Custom Fields to Achieve this.
Check it out here
You can add custom fields with full editor capabilities and specific fields like images, text, number, links, etc. You can also show these fields only for your custom post type by creating a field group and setting the ‘show only if’ to your custom post type.
It’s a very versatile and handy plugin and I use it on all my projects. Makes it easier to manage and update custom fields with almost no coding.