Tiled/stacked approach as others mention is good, and probably the best approach. Could also try doing an uncompressed format (even just .png uncompressed) or something simple like RLE then 7zip them together since 7zip is the only archive format that does inter-file (as opposed to intra-file) compression as far as I am aware.
Unfortunately lossless video compression won't help here as it will compress frames individually for lossless.
Not so. Gzip’s window is very small - 32K in the original gzip iirc, which meant even identical copies of a 33KB file would bot help each other.
Iirc it was Bzip2 that bumped that up to 1MB, and there are now compressors with larger windows - but files have also grown, it’s not a solved problem for compression utilities.
It is solved for backup - but, reatic, and a few others will do that across a backup set with no “window size” limit.
…. And all of that is only true for lossless, which does not include images or video.
Unfortunately lossless video compression won't help here as it will compress frames individually for lossless.