If Jellyfin was designed around music, then I would expect it to support gap-less playback out of the box. Albums where each track seamlessly transitions into the next are not that rare
I think what you said is a fair response to me, but I wanted to respond to this specific phrasing.
I don't think Jellyfin was designed around music. I think music was an afterthought added after the fact, and shoehorned into the rest of the experience. And then I think audiobooks in jellyfin are basically an afterthought of an afterthought.
(Again, I'm just responding to clarify if I accidentally conveyed a misconception about Jellyfin's music support)