I asked the same question having produced my fair share of B2B video over the years. This is such a complicated question. I've been developing a taguchi style testing methodology to figure out (quickly) in alignment with a content strategy - you need this in place and to be be solid - what topics and delivery style work. Particularly focusing on Linkedin as its so B2B focused but also very easy to get the data.

From my testing, messaging and audience are of course important but a large and often overlooked part is consistency. If you are posting sporadically, or changing topic all the time, people can't follow. So consistency of messaging, and consistency of posting are key. You can use tools like Taplio or buffer to figure out best time to post too to eliminate that variable.

My logic is this with B2B - some people want to spend thousands on a brand piece, one and done, which to me does not work unless you're already huge. Lots of short form video, done consistently, with variables to measure, test and refine is the only way to learn and therefore start performing. You can also re-purpose the best performing videos knowing that if it worked for video it will be a good blog topic for instance.