Slower growth was a problem from circa 1975 to 1985. By the mid-80s, the Soviet economy had problems but none of them were catastrophic (and tbf, consider how various capitalist economies right now have very serious issues but those economies are not collapsing). That was the view of Western intelligence agencies in the mid 80s btw - that there were problems but that everything was more or less fine.

A former unnamed CIA director once told historian Eric Hobsbawm that had Andropov lived another 15 years, the USSR would still be around today. I do think as late as the Andropov era, the leadership in the USSR had a good understanding of their problems and were starting to put the country on a better path. Then Andropov died and a lot of the changes made by Gorbachev and the leaders around him really threw a bunch of spanners into the works.