Front end forms, taxonomy fields, and entering multiple new terms

Hi folks. I'm brand new to Metabox but not to WordPress. I'm a little stumped on taxonomies in front end forms.

I have a CPT "Resource" and an associated taxonomy "Keywords". In the field group for Resource I have a taxonomy field for Keywords, with "add new" and "multiple" checked. I also have a view and a page called "Add Resource" for adding new posts. That's all good.

However, I want the user to be able to easily add new terms. In the back-end default post editor, one can just type "Fred, Barney" in the taxonomy box and get two new terms. If I use mb_frontend_form, I can't find any option that will let the user easily enter multiple terms. Instead, they only get to enter a single term, and then have to publish or update the post to get to enter another one. They are going to be building out this taxonomy for a while, so that's just too inefficient.

Am I missing something easy? I assume the taxonomy field should be Taxonomy Advanced, but what should the display type be? Select, Selected Advanced, ... ?? The way new terms are entered in the bare bones back end editor would be just fine for them. Is there some PHP/Twig code I could copy?

Thank you.