Thanks for the screenshots and no worries about the description as it helps it piece together.
I think the use of a multi-reference field could be what you’re looking for. You could put all skills for all of the characters in one dataset and then reference the necessary skills for each “level” (I’m assuming you’re also doing a gaming reference).
Then you can filter a skills dataset added to the page for each level to refence back to the characters so it only shows the necessary information.
https://support.wix.com/en/article/content-manager-creating-multi-reference-fields
https://support.wix.com/en/article/working-with-multiple-item-reference-fields