1zpresso released the J-ultra a few months ago, which is just a J-max with slightly smaller adjustments and something like a 1/6th lighter. It’s highly regarded for espresso and does a great job for filter coffee. But it definitely creates more fines than a grinder specifically for filter coffee, so heads up there.
To spare others the same googling: 175f = 79.4c, 180f = 82.2c.
What you’re doing is called cupping! I’ve seen it used mostly to set up tastings of multiple different coffees at once. Generally it’s recommended to stir the crust at some point so that the grounds fall to the bottom of the cup. Also, you’re brewing at a pretty low temp though. Even for dark roasts, I would consider brewing a touch hotter and see what you think.