There are people here that know way more than me, but since no one has replied, I'll pass along what I can think of.
It should be easy to just get another SW900. You might be inclined to get something else, but I think the chances of compatibility issues with your controller will go up a bunch.
Check Amazon and Ebay for SW900 LCD displays. Look at the connections and see if they match up with the ones on your controller.
that's what I would do. That is a fairly standard display, so it should be easy to replace.
A few quick links ( I have no idea if these have the same connections as yours, but check it out )
https://www.amazon.com/EBIKELING-Display-Control-Electric-Bicycle/dp/B07LBZ6KFN/ref=sr_1_2?crid=1FQMO8BYYCB7M&keywords=sw900%2Blcd%2Bdisplay&qid=1564153732&s=gateway&sprefix=sw900%2Blcd%2Caps%2C180&sr=8-2&th=1
https://www.amazon.com/Intelligent-Control-Display-Electric-Bicycle/dp/B01N3T8VD7/ref=sr_1_3?crid=1FQMO8BYYCB7M&keywords=sw900+lcd+display&qid=1564153732&s=gateway&sprefix=sw900+lcd%2Caps%2C180&sr=8-3
