Although virtually everybody else has already said about as much, I’d also say simply leaving it as oshi is ideal. I am biased due to having already picked up the term after entering the vtuber rabbit hole a few years back, but, I feel that even without a TL note, the context of its usage in a chapter like this should be more than sufficient to infer a general meaning of the word.
Retrospectively, I’ve probably been an otaku for something near 12 or more years now, I suppose. When I first started getting introduced to stuff like this, I truly never thought I’d see the day that I became one of the cliche otaku using niche jargon and loan words, and advocating for such words to not be changed in English translations. Here I am now, having had an idol otaku kamioshi for the past 3 years, and have been actively drowning in the yuri swamp for around 10 years. The internet can truly be a wonderfully transformative place, be it for better or for worse.
Anyways, back to the actual chapter. I personally actually vastly preferred Yuzu’s appearance from before the supposed glow-up from the start. The natural short fluffy hair and big round glasses from the original design definitely look exponentially superior in my eyes. But, based off current character designs, I think Masumi might actually be my favorite. Doubly so when she has her hair in the ponytail with bangs, like the latter half of the chapter.
Regardless, this is absolute peak yuri, and I am extremely glad to see it being translated here. I’m loving every single chapter.