Your magnum opus needs some work
I will start in the same order as the features appear.
Roundel of Inspiration
At first I thought this was difficult to parse, but as I started writing this answer I realised just how powerful this is. Bardic Inspiration dice eventually refresh on a short rest, and since you will have 5 and an average combat lasts 3 rounds this is pretty much every character having an inspiration every round forever. This is HUGE.
The closest feature I can think of is a Paladin aura, but until high levels that is only 10ft, and only 30ft at the most, your range is 'you can hear'. I think the feature could be ok if the range was limited, because it is a bonus action vs just inherent, but the range needs a nerf.
To address the later comments: Something to prevent this from being every round of every fight would be good to balance it. On my bards (admittedly mostly lower levels) once I have cast a higher level concentration spell I have very little useful actions in combat, so having this as an action option is really appealing. Maybe 2 dice instead of 1, but even then it depends on how often the party can short rest. I would suggest something like this feature preventing BI dice being recovered on a short rest.
Tongue Twister
This is similar to a Hypnotic Pattern with added damage, which would probably equate to a 4th level spell once per long rest. I don't think that in itself is too bad, however I can't help compare it to the Oath of Conquest Paladin, because fear is their thing and for them to be able to freeze a room and stop them moving it requires a combination of their aura (10ft range until level 17) and either a spell or channel divinity option.
I think this is probably balanced overall, but is on the stronger side.
Magnum Opus
This is where it all falls down. Once someone is affected the only thing that can help them is you taking damage, so effectively you can stun ANYTHING and then just walk up and stab it to death. As a combat feature that is far too powerful and you can decimate entire armies at will.
The ability to cast this on your death bed and never take damage again is also a pretty amusing thought, everyone you could see will never be able to move again after you die.
I don't think the feature itself is too bad, but the end conditions need work, maybe end it when you cause damage rather than take damage. Even then however there is a loophole in that your invisible friends (and you can use your own spellcasting to make them invisible if you somehow don't have other means at level 14) will be immune and can still walk around killing with impunity.
This clearly does rely on a lot of failed saving throws, but not taking damage is quite easy, especially if you have friends and those who succeed on their saves might not understand they have to attack you anyway.
Side comment
This is probably intended just for a select audience, in which case it is fine, but if you were publishing this you might want to shorten the poetic 'bits' under each power, because frankly I almost lost interest before getting to the meat.
I actually missed the mass suggestion part because by the time I got that far down I had learned to just open the spoilers and ignore the rest, turns out that was a mistake.
I understand it might mean a lot to some people and is flavoursome, but its a lot of fluff that doesn't actually mean anything and other classes don't have that kind of thing in their write ups.