Hi,
VPS doesn’t mean much, in my experience with a lot of users, VPS were the slowest, and hosting services specialized in WordPress the fastest. It’s not about your server config, but about how it is set up usually ??
Media Cleaner go through all your content, and depending on how the data is encoded, it needs to decode it. It’s extremely optimized too. You can have a look at the code, like a lot of people did in the past, some users even found a few ways to make it faster, but right now it’s pretty much the best it can be it terms of speed.
By the way, the Live Check is very slow (if you checked it). And you should also check your WordPress core speed by checking the Meow Dashboard.
Cheers ??
Jordy.