The first 60 levels are boring, but once you get to Paragon levels at 60+ then everything feels more like a challenge. It puts your gear to the test, full parties mean more. While money gets you ahead, it's certainly the time that feels the most impactful. If you can get a group of 4 to rinse repeat dungeons to grind the Battlepass, you'll exceed far more than anyone.
Run 2 dungeons, dump gear at town, go back, rinse repeat. I can see someone doing two hours at level 60 to grind gear, Paragon levels, get a bunch for crafting. Then go back to do the simple things like Challenge Rifts where you can easily place top 100, let alone top 1k and get rewards there.