I do not think that displays from a 2014 or 2015 iMac will work on a 2017 iMac. They use different display panels all together. Your best option would be to either bring it into an Apple store and see what they quote you or buy a used 2017 27” iMac like yours and swap the screen on that. Apple usually charges around $600-$1200 for a screen replacement depending on how bad the damage is and the availability of parts at the time of replacement.
There are used displays for your iMac on eBay like this one: https://www.ebay.com/itm/184392127697?epid=18034150005&hash=item2aeea094d1:g:0ZQAAOSw~EdfgJ~4#rwid
They are much cheaper than what Apple will quote you and they are not very hard to install. Check out iFixit’s guide and see for yourself: [guide|136840]