What's the necessary dump, TOSEC or Redump?
Even if you're going the custom patcher route that requires understanding the filesystem, i'd suggest releasing binary xdelta patches for romhacking.net, if they're not too big or if the first requires manual steps (it isn't likely from the size of your download).
I'd love to see more dreamcast translations but i think a process that minimizes the wasted space is necessary, something like the tool that pc-98 translations are using now that understands the filesystem and can create a patched version without manual steps (or very fragile scripts) by extracting the files, patching them and creating a new version of the filesystem that works in place of track3.bin (i think i'm right about this).
Basically it should work on wine, without a interpreter and preferably without path platform problems, so no python or wine anything like that is necessary.
Rust would be a good language because it creates static binaries by default and cargo is easy to use to crossbuild iirc.
That tool, (patchy 98) really revolutionized pc-98 translations and they're much more common now. Maybe ask for help from those guys? (though i suppose the dreamcast sega format is very different from a standard fat16 or whatever pc-98 used). One dream is to one day do a tool like that that works for most console filesystems so patches of 10 mb that turn into 1gb xdelta patches because of changed size of files are a thing of the past. I feel this is a bit unlikely because recent consoles started making their own compressed/encrypted virtual filesystems that have the same problem at a higher onion level, but the quest is noble...