One thing to note is that the big light show and fireworks are always set for July 24. While July 25 is the actual holiday, it’s very quiet that day in town and shops are usually closed. But the big celebrations happen the night before, the 24th. And there will be outdoor concerts and events leading up to that, but I don’t think they’ve been published in detail yet.
And yes, I would book early for accommodations if you’ll be in Santiago around then. It’s always an absolute madhouse, even more so this year with it being Holy Year.
Buen Camino!