lol, OK, fair enough on M&M, its been 25 years since I read it - its basically fantasy, but I have seen it described as speculative.
Dispossessed, could easily be set on Earth, space travel is immaterial and the time theory tangential. Left hand of darkness a better example perhaps.
Drowned world (and also the drought) have virtually no technology involved whatsoever, climate change angle... as they say on the right, climate change has always happened - or is Noah's ark sci fi?
Billy's adventures in S5.. are they meant to have literally happened or are they symptoms of PTSD? Skipping between events in time is a fairly standard literary device.