I gathered some detail, not much more than the overall shape, of the Romulan Flyer seen at the Romulan Cube. This is how I imagine the Romulan Flyer's hull design to be based on the photos above. The bulges on the rear must be either sensors, cloaking generators or disruptor banks.
Reminds me a bit of this https://www.thedrive.com/the-war-zo...ially-revolutionary-hybrid-electric-airlifter
Those two pics are not the same ships. The second photo is the ship Narek used to arrive at the Borg cube. The first photo shows a different vessel.