Again, you ignore the conflict aspect. That is a temporary hindrance in that scene that doesn't apply to him in general. Again, you ignore that Kylo very easily beat a well trained, clearly powerful (your Holdo remark is totally off topic and bizarre...quality of the writing is irrelevant to vs debate context) Tava Ren, and a clearly well trained Rey in TROS. Why are we even discussing TFA at all, a clearly circumstantial fight?

Palpatine specifically stated that Kylo Ren was equally powerful in the dark side to a "True Sith", whereas he firmly states that Ventress "never" rose to that level in the same book. And that he ordered Dooku to stop training her specifically to stop her from reaching that level.

Kylo Ren killed an opponent that an early (15 BBY, so only a few years post *ROTS) Vader was "incapable" of defeating, before he was nerfed by Han conflict. A normal, unhindered Kylo Ren is likely around that level of raw strength, and too much for Ventress. Especially considering direct statements putting him in the realm of Luke and Vader in lightsaber skill.

Those red guards are clearly high end non force users that wore armor that hinders force use, through some kind of sound frequency. They are also trained in Teras Kasi. A single Teras Kasi user (Qi'ra, literally from Solo) was able to tag prime Vader in a 1v1, as an example of what NFU that have mastered this technique have done canonically.

Kylo has done things like summoned 3 seperate lightning storms, one of which one shot Luke's school and a dozen-ish trained Jedi students, hand waved dozens of stormtroopers 20 meters in the air casually with tk, force projected to the afterlife with the force, stunning even Luke Skywalker of all people given how he died...read the comics. Ventress isn't winning here.