It's interesting to keep an eye on Wit Studios after their successful dumping of the production-challenged Titans. Great Pretender had a great production, and now there are two strong projects on the way.
As for Vivy, it's not a target project without high stakes - the studio's strength is elsewhere.
It's not worth watching Vivy.

But no one's going to believe that easily...

A trademark of the studio since Kabaneri is the makeup department; Manaka Naka and Ryoko Mita were in charge here. At certain moments there is a "makeup overlay" - an intensification of drawing detail with focus on the face.
You get very beautiful shots of fluorite eyes, with the color changing depending on the light.

The second strong point is the participation of animator Masahiro Tokumaru, who did the storyboard and animation for episodes 4 and 9. The ninth episode in particular was strong, with its intelligent use of perspective, camera movement, slowing down and speeding up time.

We can praise the first episode for a strong opening sequence, noting a couple of moments with the piano-playing rotoscope. The series holds up okay visually, but clearly lacks the weaving of visuals into the narrative because the screenwriter can only do crude exposition and the directors do some primitive bird-in-the-cage type stuff.

And so, Tappei Nagatsui was called in to promote a non-mainstream series. Umehara Eiji is also featured here, but Vivy suffers from everything that is characteristic of Tappei's work.

The anime is unbelievably stupid.

The main character is an AI, with a mission to make people happy with her singing. The AI has a limitation, they stop while trying to do something outside of their mission. But fmc is special, she can, for example, break faces if it's her understanding to do it for the mission. Conveniently, when conceived as a singer she actually turns out to be a tough terminator.
One can forgive such an assumption, but the degree of stupidity kept rising.

A local bad organization annihilates all AIs without exception, takes over a space station and NEUTRALIZES (but doesn't kill) the only AI that has the functionality to undo the evil plan. Very handy for future rescues and cancellations. By the way, last time these guys failed because their smart glasses were hacked by another AI. That said, no ideas, no motives revealed, just dumb guys existing and screwing up.
Parallel to this, the entire episode shows a girl who has been carrying a souvenir around for 15 years, hoping to meet the main character... and accidentally meets her on this space object. What's more, she's the only one on the whole ship who recognizes her, even though she's the first AI singer ever, and has managed to get her name in the papers. It takes more convenient coincidences to advance a lousy plot and create lousy drama.

The whole story is based on a single time travel. The traveler is surprised that after certain events are cancelled, the future he knows changes.
But it was all useless. The foolish time traveler had not guessed in a hundred years who pushed the red button. And it was a sudden villain from the bushes who devalued the 11 episodes of the series because everything made no sense. You could speculate here that the main character has changed in such a time frame, but! She's an AI. The series does absolutely nothing with this side of her, the character feels like a normal human being. In one scene she does her morning workout, why? The screenwriter doesn't understand his script. The final boss doesn't explain the conflict in any way, there's no work with the "humanity and artificial intelligence" theme. Nothing. And only the genius of the screenplay gives away a plan to save the world through song.

Work with the characters, explore the world, reveal the idea, no, exposition explains the mash-up. Sigururi, Rezero, Vivy, for the third time the same thing.
That's why the anime can be safely skipped. In terms of genre there is nothing here, in terms of production there is nothing special, in terms of enjoyment - the stupidity of what is going on passes the critical level.

P.S. On the streaming services this season there is a donghua Shiguang Dailiren with the same time travel plot: one explains how to change the future, the other performs. The series can't compete with Vivi in terms of visuals, and it's not like they wrote any special things there; but it doesn't look that silly at the time of the ongo-ing. At any rate, the writers stay out of a genre they can't handle.