Hello 
I’ve made a theme component now to achieve this…
https://github.com/VaperinaDEV/category-breadcrumb-dropdown-title
It contains two settings to make it easier.
category name
First Place: category slug
Second Place: category dropdown title
tag name
First Place: category slug
Second Place: tag dropdown title
Which will looks like this.
Adding subcategory Tag title
I hope it helps 
Edit: I fixed the dropdown width to align correctly to the custom text width. UX: fix the dropdown width to keep the custom content width · VaperinaDEV/category-breadcrumb-dropdown-title@faca71c · GitHub
