Open front boots - what makes for good protection?

Is there any evidence that some boots are “more protective” than others? or what to look for in a boot for maximum protection? I was shopping for open front boots and not sure what’s just marketing and what’s actually helpful for protection.

The Gatusos seem interesting from an airflow standpoint but they don’t have a hard outer shell like most other tendon boots … is the hard outer shell backed up by anything other than “yeah, it seems like this would protect the leg”? Gatusos has a short video of some boots being impact tested but it doesn’t have much detail (like did they measure anything or just hit the boots really hard?)
Majyk Equipe tested their boots against a couple of others, but it was just three brands https://majykequipe.com/pages/test-of-majyk-equipe-protective-horse-boots
A quick search on google scholar turned up a lot of papers about the heating effects of wearing boots, but nothing about impact protection (the goal of wearing open front boots being to protect the tendons along the back of the leg from impact).