If cell contains '?' then formula X if not then copy value

At the moment I am busy with a spreadsheet to analyse results per url. The problem is that when I want to make a list of unique urls the urls with a parameter behind it (for example '?fbads') will be seen as unique, instead of that I need these results to be blended together with the main url. See example below:

https://www.holidayguru.nl/deal/accommodatie/luxe-strandvakantie-in-ijmuiden-5e25ba62-e001-4072-8eb5-b6c3b0e7e66f/?fbclid=IwA & https://www.holidayguru.nl/deal/accommodatie/luxe-strandvakantie-in-ijmuiden-5e25ba62-e001-4072-8eb5-b6c3b0e7e66f/

Should both be: https://www.holidayguru.nl/deal/accommodatie/luxe-strandvakantie-in-ijmuiden-5e25ba62-e001-4072-8eb5-b6c3b0e7e66f/

I already fixed this with a formula but I need one list with all urls. So I'm look for two options. Or in the

=LEFT(A11,FIND("?",A11)-1)

That I use right now I need to find a way how I can say. If you don't find a '?' than just copy cell A11

Or...

I have to work with an if fuction to say, if A11 contains '?' than execute =left fuction otherwise use A11.

I can't manage to get the formula working. Demo sheet is down below :). Thanks!

Example spreadsheet