pinetreeaudio makes cables of all types, custom lengths, construction, connectors, very reasonable prices
https://sites.google.com/view/pine-tree-audio/speaker-cables/speaker-cables?authuser=0
small diameter, individually insulated strands, I used to use 8 wire (2 lines) telephone wire.
Now I make my own using OCC copper Cat8 cables, simply cut the connectors off, add WBT or other high quality connectors on. (similar but better than the old Cat 5 you described.
here’s a quickie find
NOTE: make sure the conductors are pure copper, some, only the connectors are.
AWG gauge calculator
https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html
i.e. 26awg x 8 strands = 17awg, much more than enough for home use lengths