Have used a $6, 35 foot Monoprice (fiberglass) optical cable for over a year in my main rig with nary a glitch or compliant. Tried Blue Jean USB cables (6 ft, 10 ft, and 15 ft) and for some reason the 10 ft cable didn't work well, but still considered it a win as the 6 ft and 15 ft cables weren't embarrassed in an in-home audition versus $70 - 200 cables (paid $15 for all three including shipping).
Check out any pro-audio dealer for XLR. The professionals (studio and concert) have little tolerance for high priced "audiophile grade" cables, instead they look simply for what works and is durable. And why shouldn't we trust their ears/judgements?
Good idea regarding powered monitors, but fully active (one amplification channel per driver) is better yet as the crossover moves to in front of the amps (becoming low voltage design that can be more easily tweaked which allows the amps to couple to the drivers for improved dynamics, flatter frequency response, and greater/deeper bass).