Hello,
Firstly check on the side (leftt side of your steam library) it on the left of your title you see a stop sign like but grey, this mean the game is based on a 32bit build, so it won't be working properly.

If not, check if steam is up to date, try searching if your Mac is up to date also.
Restart Steam and restart your Mac.

If you just brought the game in the last week, you can ask them a refund if it doesn't launch, just go to the Steam Support page, get the title you want to have a refund (in this case Chef RPG) and ask a refund, tell them why and wait (it also requires that you haven't play the game more than 2 hours, if not they refuse to refund you)

Yes this might be a glitch, idk but also check if it's not telling you to install the update or the game on another computer, like en old Mac or something else.


If you wonder where is the support page, you can find it on your profile on Steam (on the top bar go to Help > Support Steam), you'll need to sign in but you can also do it in a Browser like in Safari or on your phone using the app :
https://steamhost.cn/help_steampowered_com/
For the English website : https://steamhost.cn/help_steampowered_com/en/