I apologise in advance for the wall of text. Why didn't I translate "gesori"?
1. If you remove the context of the panel, I am not confident about what it would mean. If I say it aloud, I would be reasonably confident that it is some negative feeling. For me, saying it aloud I would say it gives me a "slump" feeling. But I would not be confident enough to put that down. This is I guess, a skill issue on my part. So, an extra day or two wouldn't help, unfortunately!
2. It is not an "important" sound effect. What I mean by that is, even if the sound effect wasn't in the raw, there wouldn't be much meaning lost, since it is just showing the state of Koshi exhausted and dying inside (already illustrated in the panel). However, for "pachi pachi", there is no clapping in the panel, so if you didn't know "pachi pachi" meant clapping, you would be totally lost. If the sound effect is both "important" and I don't know what it means though, then I just put down my best guess and probably a "?" to indicate I'm not totally sure.
3. I don't think all SFX need to be translated; sometimes maybe it's even impossible to have a good translation. Related to #2, you're kinda just supposed to say it in your head and evoke a feeling. In official english manga, I really hate it when they mess with the sound effects too much. Sometimes the new sound, though it makes sense in English, has a different meaning and evokes different feelings than the original Japanese one. "Donn" and "boom" are not always the same. "Donn" is "donn"! Obviously, it goes without saying that some things like "Nunn" don't really have a translation and shouldn't be translated. It's kind of like when they just skip wordplay or turn shiritori into some different English word game.
But, you are
completely right. Since I transliterate and provide translation at same time, #3 is basically irrelevant (readers can still say it aloud in their heads if they want). Plus even if it wasn't an important sound effect (#2), I could've written something like "Gesori - dying inside" or "Hamu hamu - biting/nibbling". And even if SFX don't have a translation, say "gegegege", I could at least put "gegegege - angry deer noises". It can only help readers. I guess I can even make "Donn" into "Donn - boom". "Nunn" still won't be translated ofc, since anyone reading would know what it is.
In chapter 29, which is very SFX-heavy, I put the SFX inside the panel (thank you yosoro/antipatreon scans for the very thorough clean and redraw), and translated I believe every single SFX except for "Pii" (which when you read it should be obviously the birds' sound, at least I thought so). For future chapters, before uploading to mangadex, I will add any missing translations for sound effects. Well, unless I completely don't know what they mean, in which case there's nothing I can really do about it, since I can't even provide a best guess. \