I’m in the same boat. I have a 5th grader who knows about Daddy’s game (but is not allowed to read it!) and I’ve been considering which other HGs and CoGs are appropriate for that age.
I vaguely recall that Choice of Star Captain being pretty clean. Google Play has it rated “Everyone, ages 10+”
But yes, there’s a limited number of titles with limited (or no) cursing, adult situations/themes or violence, but really the more significant problem is that most titles are written for adults, meaning they use adult-level vocabulary, assume an adult-level of reasoning and understanding and life experience, and can take hours to read. Many kids might lose interest. I think more kid-friendly titles would be shorter, incorporate some art, and tone down the vocabulary just a bit.
Sixth Grade Detective is “cute” and age-appropriate, although I feel the kids in the book acted a bit older than 6th grade (they were out and about, all over the town, etc) and the main character may explore/encounter some same-sex flirting, etc. (it’s tame) I only mention that because some parents would want to know just in case that spawns a discussion with the kiddo. All that being said, my daughter has read it like a half dozen times and enjoys getting different endings.