I have to agree with people recommending The Talos Principle, and it's DLC, as a surprisingly good puzzle game, especially coming from the makers of Serious Sam.
But if i had to pick the best puzzle game, it would be the D.R.O.D series.
https://af.gog.com/game/drod_1_2_3?as=1649904300
These are the first 3 games out of 6, and they are all (beside the RPG one, sadly) excellent puzzle games. Each game, starting with the first, uses an updated engine, i.e.: drod 1 uses engine version 1.0, drod 2 uses 2.0, etc. The good part is that you can play the older games in the newest version 5.0 (DROD The Second Sky) with all the QoL updates of the latter. Unfortunately, it seems you can't do that on the GoG version (the version i own), since there's no .hold file to export. I think the Steam version has them, but i'm not so sure. For any help, they have a forum:
http://forum.caravelgames.com/index.php
Words can't describe how addicting this series is. As of now, i'm half way through the last game, and i'm continuously blown away from new mechanics they keep introducing. Highly recommended.
Thanks for this interesting first post of yours. As I'm one of the few Codexers who plays and champions DROD, I mostly agree with your words. But not completely.
The first two games are well worth playing, as they both introduce new elements and then play around with them well enough to make an enjoyable experience, and also have well-crafted levels. But to me the third (and subsequent) games all felt like they were trying too hard to add new stuff simply for the heck of it, and didn't go far enough in making the levels entertaining. Tar, for example, is interesting because you can only attack it at the concave corners and is introduced in the first game. Mud is the inverse of it so you can only attack it on the straight edges, and is introduced in the second game. But the third game introduces gel, and gel can only be attacked on the convex corners. Introducing a new enemy with an opposite effect makes sense, but adding a third variation is just too much, no matter how appropriate it is. It's the same thing with the three types of snakes.
By the time I reached the end of the third game I was feeling pretty burned out because there were so many monsters and items to worry about, to the point that I didn't bother going for the 100% completion rate, but then the two sequels decide to add more: I played the fourth game about 80% through before I realized that I just didn't care anymore and walked away. What little I played of the fifth was like a triple dose of the feeling of the fourth, there is too much going on and not enough time spent ensuring the player digests each new feature.
(The DROD RPG is best not mentioned, even on this forum.)
And I recently bought the DROD series on Steam, but I ran into some problem with them and couldn't get them to talk to the Caravel servers, so I asked for a refund on the lot.
Now, as for games with the most intelligent puzzles... I'd like to mention (but not propose) a few puzzlers that at least strived for something bigger, but ultimately failed in one form or another.
The Fool's Errand (1987) has a meta-puzzle that involves assembling a map and arranging the pieces in the right order, so that the Fool can find the Treasure and get rich. To get the pieces the Fool must complete LOTS of puzzles, and they cover a wide range. Word games, spotting the odd one out, minor action sequences, navigating mazes, and so on. The two main gimmicks of the game are the Tarot theme that permeates the whole game, and the overall narrative that actually is essential to solving the game's myriad puzzles. It's been many years since I played it, but it's certainly a game to remember. The same guy also made a numeric/math-based game called
3 in Three (1990) and then many years later released
A Fool and His Money (2012) as a sequel to his fool's errand.