My solution to covering the hole from the Eco Stealth Hitch on a Tesla Model 3. This was in 2019, before Tesla offered their own hitch.  Has a finger hole for easy removal.  1.26 in x 0.2 in neodynium magnets hold it securely in place.  No issues in 1.5 years.  

https://www.amazon.com/gp/product/B074BP1FR8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1