We rarely get to review inexpensive convertibles that can be tweaked as much as the Dell Inspiron 5410, although the review sample already comes with a good configuration out of the box. However, the display is the main compromise.
https://www.notebookcheck.net/Dell-Inspiron-14-5410-2-in-1-laptop-in-review-The-modular-convertible-offers-affordable-performance.583524.0.html
Did you get a response from Dell regarding the USB C port and Thunderbolt control center reporting there is one port in the application?
I know 11th Gen Intel has a Thunderbolt controller on the chip which maybe what you're seeing but not sure Dell omitted the necessary schematics to provide it or is it actually a Thunderbolt port without getting it certified and paying the royalties for it?