I think any music practise needs to be done indoors with the windows closed. Almost no-one is good enough that there neighbours will want to hear them.
I had no musical knowledge growing up, but I'm learning via DD experiences.
DD age 9 plays saxophone, the only way she can play it is at full volume. It takes more expertise than she has to play quietly, if she tries to cut her volume, sound cuts out altogether.
Violin is painful in the hands of a beginner, but DD is becoming competent. I wasn't originally that keen, but I'm becoming more impressed with it as an instrument. It seems quite versatile.
There should be a law against anyone continuing with recorder after more than two years, it's an intrinsically annoying sound no matter well it's played.
Piano is the safest choice, you can play a digital piano with headphones, and even if you don't, at least you don't need skill for the individual notes not to hurt the ear. I think it's the best option for anyone who is just learning for their own amusement.