Any luck with finding a solution? Since my friend is having the exact same problem where the game launcher doesn't fully load/cuts off, except difference is that he's not running at 4k, but 1080p. For me, the launcher loads perfectly fine and just pressing 'Enter' launches the game in Definitive Edition without having to click anyting, but that doesn't seem to work if the launcher cuts off, as if he button wasn't there. Are there maybe any steam commands to, for example, skip the launcher and launch directly to the game, like the OP suggested?
Would appreciate if anyone has any useful input.