Hey Samuel!
With any repair you run the risk of damaging something in the process. It looks like you were the victim of that with this display cable, and you run the risk of damaging something if you swap the cable.
That being said, I think you have it in you to do this repair! Especially since you have already damaged something, I think that you will be extra careful this time around.
So I opened up a newer iMac and saw the other end of this cable was not shrouded in tape, which means it is a quick fix. Before purchasing any parts, try to investigate and see what both ends of the cable look like. If it is easy to access the port on the display, I say purchase the part and get this repair done! If it is buried in tape, do a little investigating to see if it is easy to uncover the port. If it looks like it might be a huge ordeal, then letting the repair pro's do the repair isn't the worst idea.
I think this is the part on Newegg too: https://www.newegg.com/Product/Product.aspx?Item=9SIA9053W41195&ignorebbr=1&nm_mc=KNC-GoogleMKP-PC&cm_mmc=KNC-GoogleMKP-PC-_-pla-_-Mac+-+Accessories-_-9SIA9053W41195&gclid=CMyg1IXHhNQCFYF9fgoduJgIkg&gclsrc=aw.ds
Let us know what you find!