Please check here … how about (additionally) running Nik 3.x as plug-in for old PS.
In case you don’t know Affinity Photo 2, you might give it a try. While (of course) the handling is somewhat different than your CS6, it runs really good – and supports Nik 5 … just in case you need it. AP2 comes with a new installer type, but after a lot of complaints, Serif added a compatible one.
If you need help … PM or call me. Wolfgang