Did Creative Cloud uninstall will uninstalling Photoshop CS6?

As soon as you install any part of the Cloud, even a trial, it replaces your program management system
-if you plan to keep using a serial number program you should NOT install a Cloud program, not even a trial
-Read Cloud takes over https://community.adobe.com/t5/Get-Started/Get-off-the-cloud/td-p/8075485 for some ideas

 i'm not sure what you mean by "incompatible" hardware but you can't install the cc apps on an external hard drive (and expect them to work).

so, if you want to use your trial, you should install the cc desktop app and use it to change the install location of your cc trial programs to (an allowable) hard drive.  if you want help with that, reply

to answer your question, uninstalling cc won't uninstall cs6 but your cs6 license was probably taken over by the cc subscription (free or not) so you'll probably need to return here for help restoring your cs6 perpetual license.

if you want help with info on how to properly uninstall cc, reply.