Access Selected Taxonomy on Insert/Update from Frontend

According to the taxonomy field type, it does not store the taxonomy to the database (but changes the taxonomy id of the post - which is in the database, so that's confusing). Regardless, on if I add a taxonomy field to a front end form, it is displaying all the terms of the taxonomy, and even pre-selecting the term if it was previously saved in the back end. However, I can not get this value to update when saving from the front end.

Metabox:

'name'       => 'Veranstaltungs-Kategorien',
'id'         => 'tribe_events_cat',
'type'       => 'taxonomy',
'taxonomy'.  => 'tribe_events_cat',
'field_type' => 'select',

I have tried using an id of:

tribe_events_cat
tax_input[tribe_events_cat]
tax_input[tribe_events_cat][]

with no joy.

I am now looking to hook into:

rwmb_frontend_insert_post_data
rwmb_frontend_update_post_data

to see if I can access the selected taxonomy value and manually update the post_id with the updated taxonomy term_id, but I was wondering if there is a recommended method of dealing with taxonomy and category fields using frontend submission.