I had a similar thought: my first version of that line was something like "It's always 'so cute' this, 'so cute' that with him.", but I wasn't a fan of how it read and decided that the dialogue reading better took priority over not putting in something artificial. The reader either gets a line that doesn't fully align with the conversation (in my opinion, you have to "squint" to interpret the example I gave as talking about Chitose), or they get a line that does align with the conversation and sounds natural apart from using a nongendered pronoun, which adds a "false" nuance to that sentence that isn't there in the original, but at least the "falsehood" gets clarified in the notes. Granted, I could have gone with the first option and also put a note for that, and maybe some readers would prefer that. But ultimately, my philosophy is "readability slightly edges out everything else" and I use notes to compensate. In fact, I was originally considering putting an asterisk and a "see tl notes" after the "they", but I figured that that wasn't necessary since the notes directly follow this page. I'm sorry I don't have a better argument.I understand Japanese language being able to skip pronouns poses serious challenges for translators, sometimes leaving little choice but to add "they", but I still can't help but find it weird. After all, there zilch chance Nagisa actually would use a gender neutral pronoun when talking about someone whose gender she absolutely knows. So, it looks 100% artificial in dialogue, no matter if it's used to try to represent the Japanese ambiguity in the English translation.
I fear I'd be an immoral translator because I'd change it to something like: "Sneaking glances and calling someone cute all the time. It's so obvious." It wouldn't be a direct translation anymore (and it would contain stuff that wasn't even in the original), and I'm not sure it would be overly smooth spoken language either, but it would avoid that "they", which looks unnatural when we know she definitely wouldn't use it if she was speaking in English.
I had a similar thought: my first version of that line was something like "It's always 'so cute' this, 'so cute' that with him.", but I wasn't a fan of how it read and decided that the dialogue reading better took priority over not putting in something artificial. The reader either gets a line that doesn't fully align with the conversation (in my opinion, you have to "squint" to interpret the example I gave as talking about Chitose), or they get a line that does align with the conversation and sounds natural apart from using a nongendered pronoun, which adds a "false" nuance to that sentence that isn't there in the original, but at least the "falsehood" gets clarified in the notes. Granted, I could have gone with the first option and also put a note for that, and maybe some readers would prefer that. But ultimately, my philosophy is "readability slightly edges out everything else" and I use notes to compensate. In fact, I was originally considering putting an asterisk and a "see tl notes" after the "they", but I figured that that wasn't necessary since the notes directly follow this page. I'm sorry I don't have a better argument.
Also, I would've been more screwed had this come out before singular they was as accepted as it is now. Hopefully in the future translation problems like this will be easier to overcome.