Blender - Alternative workflow for Cryptomatte?

Hello everybody, Using Blender 4.0, been working on a shot of about 350 frames,3840x2160, simple animation nothing much with motion blur, the usual workflow for me was to render out multipasses and Cryptomattes and comp them, but due to the large number of frames, the utility and Cryptomatte file size becomes exponentially bigger now. So tried out DWAB compression for the cryptomatte which broke when compositing,

Found a workaround to reduce file size using Pix24 format and recompression using DWAB in nuke was able to cut to about a quarter where the crypto worked fine even after the compression.
Seems just Blenders DWAB output Breaks it. which was not the case for Utility passes. just cryptos

still wanted to reduce file sizes due to cryptos being overkill for a simple animation of object moving from A to B, found IndexPasses which seemed to do the trick, but do not come with motionblur as with cryptos, how do I render motion blur while motionvectors are enabled?

For this case, you will have to disable renderer motion blur and apply using the Vector Blur node in the compositing stage, or in another compositing software.
Thinking about storage, usually I render out two openEXR multilayers, a half 16-bit for color and a full 32-bit for data passes. Mist, environment and AO also goes to the first EXR. But for a 350 frames animation you shouldn’t worry about compression, it will only delay your work. I suggest rendering 1080p, and look for AI upscaling tools. Far better render times and lower storage sizes.

The bug was fixed long ago except for File Output nodes and the “save as” dialog.
Not tested.