The Sdefa word you gloss as "end" in your translation of the beauty of the house (DEF♯A) is different from the word you glossed as "end" in your translation of the left hand of darkness (A♭GD♭C), is this a deliberate vocabulary change, a synonym, or accidental?
Good catch! There are, as far as I can tell, four ways of saying “end” in Sdefa, with slight differences.
One reason for this is to allow for greater flexibility: say you’re writing a bit of Sdefa and so far everything fits nicely into D major, but then one word doesn’t fit so well within that key. You could pivot and make a key change, or have one chord that’s a bit out of left field… or you could choose a different word that fits better in that key.
Also, I do sometimes make mistakes and make a new word when I already have one with that meaning. Usually if this happens I try to differentiate them in some way after the fact, though.
Anyway, here are the different words for “end”:
The one in the translation of The Beauty of the House (from Piranesi) is {D E F♯ A}. This refers to the end of an event or period of time specifically. The most literal interpretation of “[the house’s] kindness [is] infinite” using this word would therefore be that the house is kind forever, that it will never stop being kind.
The one in the translation of The Left Hand of Darkness, {A♭ G D♭ C}, is “end” as in “goal” or “destination” (think “means to an end”). You could use this interchangeably with the first one if you’re talking about the end of a journey, for example, but it would still be the destination of that journey even if it was never completed. And this word wouldn’t make sense in the Piranesi quote, because it doesn’t refer to kindness being without a goal. I think you could make a case for one of the other words working in the LHoD quote, but the pairing of “end” with “way” in that case makes me think of this sort of “end” first. I guess that just means it’s a bit of wordplay in English that doesn’t translate directly into Sdefa.
Another word that could be translated as “end” is {D E F E}, which is also “edge” or “boundary.” I think you could also interpret the original quote from Piranesi as meaning “it has an infinite supply of kindness,” in which case this word might be a more literal fit than {D E F♯ A}. However, I think both work and that one was a better fit musically. Or maybe I just didn’t think of this word at that time.
Then there’s “end” as a verb, {E G D B}. Obviously that wouldn’t work directly if you want “end” as a noun, but there’s always the nominalizing prefix so {F D E E G D B} would work to mean “ending,” “completion,” etc.