Both Delta going down and Quantas coming back were comfortable enough. In both cases, I was able to recline enough and put my feet up and get some sleep; husband more so. I felt there was plenty of leg room. I think the A380 was somewhat more comfortable than the 350. It had compartments under the window that fit purses, pillows, etc.
I might do such a long flight again but would need a stellar destination. That didn’t involve long long bus trips.