Just providing more info on the topic, had the exact same issue, and fixed it. Also tried reinstalling DCS World completely, tried repair, checked runtimes, et cetera.
The problem was in the japanese keyboard layout, after the last update DCS decided that it doesn't want to work with JP keyboard layout active anymore (Although it performs exactly as default EN layout until switched to kana mode by Alt + ~ combination), and after i removed it and added back a standard EN one, it stopped hanging on splash. Hope this gonna be helpful for someone.