What Is The Best Approach To Enable Users To Create Their Own Categories & Tags That Can Be Used To Filter Their Posts?

UPDATE!

I think I’ve figured out how to enable users to create and select multiple tag options. I followed this recommendation that has a link to a video:

I’m also able to show only the tags associated with a category

See here:
IMAGE #1

IMAGE #2

This is the logic I did:
IMAGE #3 Add Tags Input

IMAGE#4 Event for when the tag’s multi-drowdown’s value changes

IMAGE#5 Create a new tag action

IMAGE #6

I’m Still Stuck With Two Tasks:

  1. Trying to filter posts via categories and tags on the user’s profile page.
    (Specifically: When a category filter button is selected - show all posts with that selected category. By default, the first category button should be selected.
    When a tag filter button is selected, show all posts that has that tag and the selected category it belongs to.
    Furthermore, when the tag filter button is de-selected, revert back to showing ALL posts of the selected category.)

  2. Dynamically display only the tag filters on the page that are associated with a selected category