To be honest, you'll probably get pretty much the same speed from any of the popular blog extension. There's not much you can do wrong from a performance perspective with a blog extension. It's a pretty basic CRUD app. (I'm sure some developer can prove me wrong though).
If you're worried about performance because of images and video, the problem here is more likely to be frontend speed. I'd recommend ensuring that the images are optimised to avoid wasted bandwidth. If you want to go above and beyond, I would recommend customising the theme so that images are lazy loaded in that way they don't delay page load if they're not in the frame of the page. That's above and beyond though.
Videos I'd recommend hosting elsewhere. Hosting for Magento isn't going to be optimised for hosting large videos files. It'll be much cheaper and more effective to host elsewhere and embed into your blog posts.
Finally, I'd recommend getting a CDN set up, like CloudFlare which I love. It'll reduce the bandwidth costs by caching these kinds of assets.
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