My exact experience more or less. I played it with a companion for an hour, we breezed through it until...a dragon 1 shot us 3x and done. I also realize the draw of different styles of game play, (there are only X amount of directions Zenimax can go in). I also found someone had played it for 13 hours straight. I believe endless archive (if/when balanced) can be another great edition to a game that, while it has many many issues: block bug, UI errors, routinely introducing old bugs with new patches lol...has given me more than I bargained for, in a good way.I don't share the positive impression of Infinite Archive (and still need to get used to the name change after the last patch), but I can see why people might like it and it definitely adds to the variety of gameplay experiences, especially considering that it is for solo or duo.
I don't particularly like breezing through several bosses only to get constantly wiped by the next one all of a sudden because he has a hard-to-see insta kill attack and if you don't know how to see it coming or protect yourself from it, you're one-shot. Repeatedly. Until after the third time you have to start from the beginning.
Might be different depending on your build I guess, or if you use combat alert add-ons etc, or are teamed with another player instead of an NPC companion.
It drops nice new furnishing plans and other loot though.