Sorry for the inconvenience. I will write down some things for you guys to try. Feedback from you about these trials will help us to fix this asap.
1) If you can not see even the launcher, you can try the following: Go into the 'steamapps\common\Mount & Blade II Bannerlord\bin\Win64_Shipping_Client' folder and writing 'cmd' to the windows explorer path bar and hitting enter. There should be a command line menu popping up, can you enter the following there and press enter to try launching the game like that:bove Bannerlord.exe /singleplayer _MODULES_*Native*SandBoxCore*CustomBattle*Sandbox*StoryMode*_MODULES_ /anticheat. If the game works, that means the launcher is not working for you for some reasons. We will check it out.
2) If the game is still crashing with the command above, there may be some missing dependency. In order to test it, you can use another exe(Bannerlord.Native.exe) with same procedure as above. If there is a missing dll message box popping up right after the launch, it is a clear indicator that some of the dependencies are not installed by the steam. You can download them through this link:
https://forums.taleworlds.com/index.php?threads/game-failing-crashing-at-launch.397007/. After downloading them it should be able to run easily with the exe in the first step.
3) If your game is still not running after the steps above, we would like to get your game log(the one that starts with 'rgl_log_errors') which you can find in the following folder:
"C:\ProgramData\Mount and Blade II Bannerlord\logs"
Sorry for the late reply. Hoping to fix your issues as soon possible.