The other way I look at it: TNG was following the premiere ship in the galaxy, with plenty of places to explore, so it was always encountering “new frontiers”.
The Orville on the other hand was more a premise of “what happens when space travel is commoditized and you have more than enough ships and now need competent bodies to staff it?” For that it feels more “real” that you’re getting people who do it as a job, not a calling, which explains the random humor and diversions and a look at new discoveries through fresh eyes rather than “wow, more new as this is normal for us”.
I’d say TNG mostly stopped exploring new frontiers halfway through season 1. Farpoint promised exploration, but soon the ship is ferrying diplomats and scientists and answering Federation distress calls. The worlds are new to the audience, but not the characters.