I may have figured out why this plugin is not updated anymore.
I added the Taxonomy field, set the option to post_tag, then set the options to multiselect, don’t allow users to add tags, load post tags, and connect tags to the post.
This pretty much works the way I want it too. It is not exact because there isnt exactly a search box with autocomplete, but typing in the field will filter the results. So that works close enough.
This is after I built my own version of the tag field, that populates the tags from wordpress and updates them as well. I’m not sure how i missed the taxonomy field though. I thought I tried the field to see if it would work. It looks exactly like the field I made, so i am probably just going to use it.