I'm a long time user of quicksilver. Open source. Long time loyal users swear by its ux for efficiency. Development has slowed down recently, but it still runs great for me.
The issue with the spotlight engine that everyone uses is that it excludes "hidden" directories and in particular every dot file and dot directory.
Spotlight is built in, but Alfred’s also a good one.
I was looking for Everything for Mac and tbh I can't say Spotlight is even close. Sure Spotlight works great for apps and files in ~/Documents/, but I find it failing when I'm trying to find some obscure file in /Library/ or with-in Xcode SDK's.
Is Alfred good in this sense?
I used to use Alfred for this, but it's not really the same as Everything. I'm not sure why - something about the speed, results or maybe just the interface itself.
Some of the Windows tools use the NTFS / USN change journal for very fast access to metadata without traipsing across the rest of the filesystem. I dunno if APFS has such a thing?