Opening it now just says "Microsoft Edge is the new home for PDFs!"
Edge is unsurprisingly not a very good PDF reader.
Edit: The thing that has impressed me about preview is that I can use it for very basic image editing, filling out forms (with signatures), and reading books. And it is very good at all of those. So that is what I would want in a replacement.
It is relatively lightweight, can be used without a formal installation (i.e. no admin privileges required), and I like very much that it stores its state between sessions, so when I open it after a reboot, it has all the files open I had open before, and it also saves the position within the files.
Searching within files is not as good as with Apple's Preview.app, but most of the lengthy files I view have decent TOCs, so it is not a big problem for me.
It's the first thing I disable.