As a more immersive (and larger) version of the Blood Tank, the Ritual of the Sphere would create a floating... sphere... that expands depending on the liquid stored in the Ritual.
It should have a constant (low) cost up to a specific amount of LP and after that increasing cost dependent on the liquid stored.

Maximum liquid could be configurable or Integer.MAX_SIZE.

Fancy render thing!
Could look like a galaxy (big blob in the center with smaller blobs floating around it).
Adding and removing liquids with BM liquid transportation or Fire/Water (Dusk/Dawn) ritual stones acting as in/output (by placing any Blood Tank on them?).

(Totally didn't draw inspiration from the AstralSorcery Containment Chalice or Draconic Evolution Energy Core/Reactor)

Suggestion/enhancement or invalid and close (for addon).

We draconic now boiz

Interesting idea...

Liquid falling out over the landscape would create a giant mess. Considering that my idea was that it'll increase in cost based on the amount of liquid stored, it will in some (many) cases be disabled just because people forget about it or general carelessness (running out of LP) for which I thought it would be "better" to lose everything except for a specific base amount (not to mention that such a fallout would be very hard on the server).

That being said, a symbolic leak of a couple blocks would definitely be possible.
Maybe something like this:
"Only a fraction of the actual liquid is stored in this dimension for stabilization purposes that doubles as a measure of the stored liquid. One downside is that failing to power the ritual will result in losing most of the liquid stored. You are not quite sure what would happen with the part stored in this dimension."

I had something like that in mind.
Earth anchors it (in this dimension) and provides liquid in-world to be able to be taken out with a bucket (or similar).
Air lifts it up (the sphere in the air).
Fire for input (evaporates), Water for output (flowing).
Dusk accepts liquid source blocks ("consumes the sun").
Dawn contains the sphere (the sphere resembling a sun that rises).

What happens if the ritual is broken or deactivated? Does all the liquid fall out over the landscape?

Well, I wouldn't dump MAXINT blocks on the server (!), but dropping a few hundred blocks of liquid (perhaps filling the volume of that ritual form) would be a reasonable "industrial accident".