How does cable length affect sound?

I hope I’m in the right forum.  I have a listening room 18’ X 22’.  My speakers with monoblock amps will be on the 18’ wall.  I would rather have my preamp, transport, dac, etc., on the 22’ wall close to my seating area rather than between my speakers/amp. I have dedicated 20 amp outlets on long wall but will need, at the minimum, 11’ power cables to make the connection to the outlets.  I will need approximately 18’(?) of interconnect (preferably balanced) from the preamp to power amps (running along perimeter of room).  Will these lengths of interconnect or cable degrade the sound or is there any specific quality I need to be aware of when purchasing them (if they make them that long)?  Also, should the power cables be of equal length or can they be of different lengths?