Albums in ZIP or single MP4 or alternative

I have an external USB HDD that mostly contains MP4 videos, about 100 MB to 2 GB each. To store and retrieve those more efficiently, I formatted the drive with a rather large cluster size – 4 MiB if I remember correctly. Since every cluster can be occupied by a single file only, this would waste a lot of space for smaller files like plain text documents (including playlists), images, music tracks and audiobook chapters.

However, I want to put part of my audio collection onto this drive without reformatting nor partitioning it and without too much wastage. Therefore, Iʼm considering to put each album either into an (uncompressed) ZIP archive or into a single MP4 container with chapter marks. Whatʼs better supported by playback and managing apps, in particular on Smart TVs? Is there a better alternative Iʼm not seeing yet?

If you can stall this operation- then wait as long as you can and look for another drive; i.e. buy a new / bigger one than the current one and hopefully for less. Although I know from my own experience that huge HDDs costs today as much as in 2016 and large SSDs are now more expensive that in December

Or if you cannot wait and will not be able to afford a new one in the foreseeable future, take extra time and effort in finding space on your other drives and temporarily load them up with the content of the drive in question - so that after all you can format it. Or use Blu-ray for that, as the prices of a single 25 GB disc have finally dropped to a "normal" level - assuming of course you have a BR writer available to you