Is it the photogrammetry which looks awful?
If so you could try disabling that under Settings → General → Data. If I understand the scenery mechanics correctly, this should remove the photogrammetry buildings, replacing them with autogen buildings which the OrbX scenery pack can then override. I don’t own the scenery pack, so I cannot test this works, but I think it will.
By doing that you would still keep the rest of the world update installed, which will let you keep the airport improvements, and POIs. There may still be some graphical conflicts until the updated London City Landmarks pack is released in a week or so.