I've been playing some Fallout games past month. I never got too far on F4, so I started with that. I enjoyed playing it on hard, surprisingly. For me, it's all about exploration, and finding curious things.
But those loading times. It's easily a minute of waiting when going from indoors to outdoors. They apparently goofed and throttled loading by the game's framerate...
So I picked up Fallout 76 from sale a week ago. It's not as bad. Quite a few QoL improvements. I even liked the new real-time VATS system.
As a single player experience, I think it's too expansive. Roughly 3 times the size of F4. There's so much nothing between mission markers, and you'll be backtracking for hours. It's clearly a byproduct of the whole multiplayer experience. Although I haven't reached nearly all destinations yet, but so far it's been pretty samey, and what landmarks you come across, you'll be lucky to find even an ammo stash.