If you swap over the speakers, does the broken sound still come from the original right channel speaker? If yes it’s the speaker, if no it’s the amp or somewhere up stream.
id be surprised if its the electronics if the tweeter still works regardless - they will either output the full signal or nothing rather than just the high frequencies - so i see you’ve flipped the cables, is that form left to right or a different set entirely? does the fault stay on the same speaker or move with the cable channel swap?
If disconnecting/reconnecting all doesn’t cure, then more info needed -
1)Is it with all sources?
2)Were speaker cables swapped at amp end or speaker end?
When you say losing mid/bass, what does that mean:
3) Silence from both mid-bass drivers or audible but reduced level from them relative to tweeter?
3a) If latter, with ear to one of the mid-bass drivers, and cushion or similar held gently against tweeter, listen to the mid-bass output, then repeat with the other speaker but first reducing volume so the mid-bass is similar level to that you just listened to on the bad channel. Does the balance of sound from each channel’s mid-bass driver sound similar to the other, just that difference in volume?