I’m guessing everything was working before swapping cables. If this is correct, is it possible that you swapped cables while the system was powered up? If so, you could have damaged your amp or your speakers.
if you hook up your left cable to your right speaker, does it work?
Do you have access to another pair of speakers, it doesn’t matter what they are, you just want to see if both work.
If the new speakers work then it’s your old speaker. If it doesn’t work, borrow An amp and see if that works.
Trial and error.
As for easy access, put your gear on top of a taller table so you do t have to bend over the change or check things out