Very hard to unlatch the rear engine hatch

It probably needs adjustment. It may seem like overkill but the best way to deal with it (safely) is to remove the rear lights first because if you get it wrong & it really does stick then you are screwed. With the lights out the way then you can always get to the latches & you can also use a small mirror to look at how the thing is aligning as the deck comes down as well. While the lights are out you can also give them a good clean inside & out & also clean up the paintwork surrounding them.

One good idea I saw while ago is to adjust the cables so that the latches don't quite pop together but rather one after the other. To do it you leave a little slack in the cable between them. That can significantly reduce the strain on the cable I think.

 

Yes, there's one cable that pull both latches but it does split before that as one goes to the back-up/emergency pull.