Since the game, Gravitas Magica : Rhythmic Sunrise, isn't ready, hence I will kindly skip on rating the game. Still I would like to discuss about the plot and concept with what is currently present from the main page and comment section.
So the story is about a retired magical girl now an office lady who one day found out that the sun is burning hydrogen at an abnormal rate, possibly someone is behind the mischievous act so our office lady has to come back into magical girl service to save the human race from extinction. Basically the plot sounds interesting and I think the beginning of the story is fine but I can't imagine just yet how the story would evolve down the line since its pretty much open ended at this point.
From the screenshots, I assume there will be an inventory and item system while the player character is allowed to move about in a 3D environment with stuff that can be interacted. The tank movement controls using the virtual control is fine if the aim is for a mobile device but since it is mentioned in one of the comment that it will be a HTML5 release so its best to change out to a keyboard and mouse control setup instead. Just something from my experience working with the audio system in Unity, the rhythm battle system might be a difficult setup even with the tutorials since in Unity the game time by default runs on a separate time system from the audio system which uses the AudioSettings.dspTime, so happens it never syncs well with one another. So this leads to an intricate setup where you have to make the existing components sync up along side the dspTime. One of the component mention in the tutorial is the animator system but later you may have to consider button press events and coroutines with further development down the road.
Besides that, this might sound discouraging but you might want to consider scaling down on development. In my opinion, I would cut out inventory and item since that would take a lot of time to craft and plan while focusing on the rhythm battle instead. It would feel redundant to some players when you have an inventory and items system and there is only a few usable items with no way of buying or selling those items... Which also requires currency and ways to earn currency. Besides each item would apply an effect which requires pretty much needs individual scripts for them. However its pretty much your call to make towards its current development.
By the way, I tried the game on a Oneplus Nord with Android 11 and the game is giving me a steady 60fps with no issues on Chrome.