Despite claims to the contrary by the usual suspects it will take about an hour, maybe an hour and a half if you take your time. It's fun but fleeting, just enough to give you a feel for the basics.
You can do some replays to up the play time of course. My favorite class was the Wizard followed closely by the Barb. Monk was pretty cool as well though hes balanced a little weirdly.
Playing: Subnautica Below Zero, Mass Effect Legendary, Resident Evil The Village
Watching: The Banishing, Bad Banks, Ted Lasso