Haven't seen The Boy, but yeah reading about it it sounds similar to the first episode, but after that I doubt they're very similar.
I can't remember if you're hot or cold on Shyamalan, but if you dig his visual style I highly recommend, his episodes look amazing, there are great performances, and it gets progressively creepier as it goes on. It's also weirdly one of the best food shows, and they use that to horrifying effect. I said this before, but it basically created a new yuppie nightmare subgenre of like house torture porn, where you see this amazing home literally decay as the show goes on. One of the few creepy shows to stay consistent, stick the landing, and not overstay its welcome.
The house in Servant is amazing, even if they seem to keep finding new spaces in it in the later seasons.
The exteriors are real, but the inside is a set. Photos of the actual house: https://www.redfin.com/PA/Philadelphia/2108-Spruce-St-19103/home/38228698
I always root for and mostly enjoy Shyamalan, but when he stinks, he stinks. I will definitely check it out when I inevitably get Apple TV again simply for season two of Severence