After playing with the Void shields for enough time, I think it will be a nice addition to make a stationary shield generator contraption, which generates a Void shield around it thus protecting it against projectiles and attacks. And blocking mob passage alongside players unless they are added to generator's whitelist.
Essentially it will be using the shield but in different forms.

It could have the shielding area setting (range), reflectivity, but not durability. Essentially, it is being both area denial and area defence.
All because this type of shield works in a different manner: instead of generating in front of the entity, the machine of the generator replicates the casting property of the lenses and gauntlets, and kinda multiplies it to create a sphere around the machine. The durability of the shield is not set due to one reason: the shield stays up as long as there is energy. But should the energy be drained or obstructed, the Void Shield will not be able to be functional without support.

And here come the costs of having such defence: while it will be hard to attack thru it and all of that which default shields have, the upkeep is not the cheapest one. Not only it will need to have a constant stream of vis and probably even impetus and some related essentia (like Praecantatio, and maybe some additional ones for the form, maybe Alienus) to keep it working, but any attacks on the shield will drain more power depending on a damage value. Worst part is: if the damage is too constant or way too high for it to handle, the shield generator will have some nasty effects due to essentially being overloaded, causing instability around the generator and probably whatever links power to it like an impetus matrix (unless there is some shielding on the machine to keep the storage safe from the surge), give warp to anyone near the generator, generate flux and increase it's amount in some chunks, possibly break the casting lenses on the machine unless special upgrade is installed, and if the damage is WAY too high and common, it will perhaps maybe even straight up explode.
The machine itself could have some upgrades or autmentations, which increase the storage capacity, reliability, and maybe block some of the damage.
If more generators are placed and they overlap, if possible, they could perhaps share the same values added to each other, like power drain and while durability. But not that far, so stacking generators will not be a good idea.

Same applies for the Barriers, but they are rather one-sided wall rather than a cupola. Still, it can block the entryways and doors if need comes. Can come in the form of a focus, I think.

Void shielding conduits can be a way to automatically cast the void shields of different types on the entities near it if the special bauble is equipped. Also may serve as a linking points for the shield networks. And, maybe as a misc, but within the Void Shield generator area, those could act as an expansion for the machine, creating smaller shields. Will help customising the shield shape and etc.

So it will be better if such shields are reserved for emergencies, as the upkeep costs and possible risks would not allow to keep it running constantly unless player somehow has a lot of resources.

Then there are smaller things, like Special shield, enhanced by the void shield coating, and powered by storage within that shield.

As for Void Shield sphere, it could come as an enhancement of the current void shield focus, by not only being able to set the size of the sphere around (or make it so it adjusts to the entitiy it is applied to in size), but also the ability to make a spheric void shield. It will cost way more to cast and will affect the ability to add more of the rest of the shield abilities, but will completely encase the user in a shield. Imagine a void-shielded iron golem, or even something bigger.
Maybe, when tied to the Special baubles and conduits, one can place a battery on himself and keep that shield operational around you or anything you set. The counterweight is obvious: less of a durability, more costs, and perhaps some limitations to it as well.

Technically, you can give the Autocasters such shields as well. .-.

But I think this idea will be useful, as the Void Shields can be used in SO MUCH creative ways that it is only a matter of time.

While this is a very cool idea, its use is pretty situational and too specific. If there there is going to be some sort of invasion event style thing from like peches or the crimson cult, this could be a perfect fit for it, but now it would serve hardly any purpose. This voidshield would only be mainly used in multiplayer, at least thats what I would think.

Kinda. Also might tie-in with my previous idea about the cult.

Then again, you can probably also make a floor out of the shields and use it as a drawbridge...