For all “intermediate” purposes, I have only two recommendations: either OpenEXR, or, more likely MultiLayer OpenEXR.
Both of these formats are “expressly designed for the purpose” of “capturing render results.” These files are not meant to be viewed, and they’re also not meant to be small. Instead, they’re designed to be “loss-less,” and numerically accurate.
“OpenEXR” is the original format that was created by Industrial Light & Magic (ILM), and “MultiLayer” is an extension to that format (which was actually pioneered by … the Blender Foundation). “MultiLayer” allows multiple “layers” of related information to be captured in a single file. (It was a Very Good Idea™, and The Industry adopted it.)
In every rendering or image-manipulation stage within your pipeline, no matter how many stages there might be, except for the actual production of “delivery files” (such as .MOV), the most-important thing that you require is “loss-less accuracy.” You want the inputs to stage “n+1” to be "exactly ‘the outputs of stage n.’ Which is exactly what these file-formats, in particular, undertake to do.
I suggest that “the ‘final-final version’ of your movie” ought to be: a directory full of OpenEXR files, one per frame." All of these have been laboriously generated at a visual resolution equal-to or greater-than that of any deliverable which your project may require. (Likewise, each-and-every intermediate stage used the MultiLayer OpenEXR format.)
If you follow this strategy, you know that this “final version” has never yet been “compressed.” It has never yet been “encoded.” Data has never been “lost,” and you have “directories full of humongous(!) files” to prove it!
From this, you can now (separately) generate “movie files” in whatever format and image-size may be required, knowing that each one of these is a separate reduction from “T-H-E Master.” Knowing, also, that this is the one-and-only stage in which “actual data” was encoded and/or thrown-away and/or compressed. (And, knowing that the original sources remain unchanged, so you’ve actually ‘lost’ nothing.)
And, “disk space b’damned…” These days, disk drives (and SSD drives) are cheap, gargantuan(!), and external.