After seasomimg your own way pan-fry the steak for 7-10 seconds per side to seal the outer layer, keeping the juices in, then grill.
That doesn’t “seal the juices”, this is a fallacy.
And 7-10 seconds does nothing.
You want high-heat to get browning and the Malliard reaction, which is Flavor with a capital “F”. You need cooking to get the interior warm.
Oven cooking at low temperature, say 225F, until you reach about 125F internal temperature, then a short stint on a blazing hot charcoal grill to brown, is a pretty good but unconventional ticket to a great steak.
If you don’t have a charcoal grille, the Alton Brown frying pan method works well.