I've been having the same issue lately with export zip files from Construct 3. I found a way to make it work, however after that I am having an issue with making In App Purchasing work which may or may not be related, but here's what stopped the XCode crashes for me.
1) Make sure your app is at least 25MB or larger for downloading (this will become important in Step 4), if it's not that large, simply import any video file large enough to put you over 25MB, you don't have to use it for anything, just import it into the app.
2) Now export your app using the iOS-Cordova choice, with the XCode Project option.
3) Download your app's .zip file to a WINDOWS PC (These steps MIGHT work on a Mac, but I haven't tested that.)
4) E-mail the .zip file to yourself using a Gmail account (if it's over 25MB Google will automatically make it a Google Drive link instead of just the .zip in the e-mail, which is what you need for this to work.)
5) Now go to your Mac and open your Gmail with Chrome.
6) DON'T click on the normal link for the file in the square box lower down in the e-mail that probably says "Not virus scanned" under it (This will result in the same crash when trying to open the .xcworkspace file with XCode.
7) INSTEAD click on the upper link for the .zip file (not in a square box), this will load a mostly black screen with a listing of the .zip contents in it.
8) Use the download button near the top-right of the screen (looks like a down arrow above a line).
9) On the next screen click the blue "Download Anyway" button
10) Now unzip as normal and double-click the .xcworkspace file, in my experience it will now open correctly (after you choose to "Trust and Open" the file)
If you are still having issues, try using a different unzipping app. I've had different results unzipping the file with different zip apps, but using "Archive Utility" always works for my C3 exports. (That's the one with a green square icon with a silver zipper running down it.)
Doing this allows me to open my apps in XCode, however as I mentioned earlier I still get a problem with the IAP that may or may not be related. Issue is the Store Registration never completes. I will be putting in seperate post for that issue.
Hope this helps you!