This is going to be even worse than reddit search, unfortunately. There’s not an easy way to make a search like this scale for the small amount of instances we even know about. Considering there are tons of instance out there and there will probably be more in the future, these problems are going to crop up a lot more. It’s actually much easier to search in one centralized location, however the reddit search actually ended up being implemented.
I’m basically in the exact same boat. Used namecheap forever, and sometimes use route 53. They both work well