I use Sim Dashboard on and off on the cheapest Android tablet I could find (not sure if it's on iOS as well). You can build custom dashboards with a ton of info, but I mainly use it when my FOV doesn't allow me to see the tach on the car I'm driving. You can download it for free but you're limited to three "widgets" per dashboard which is very basic. If you decide you like it, you can pay ~$13 to unlock the full version with unlimited items per screen. You have to install a server app on your PC, then it talks to the tablet via wifi or USB tethering.

I got this from amazon and have it mounted directly behind my wheel. It cuts off the bottom of my middle screen, but what do I need to see an empty dashboard for anyway?

https://www.amazon.com/gp/product/B0789GJ8T4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1