I've finally managed to get it to hold the bazooka with both arms, so I'm posting this progress update.

I realized it's been a month since my last progress update...
https://gn-app.com/posts/df568c5e-36dc-4a82-84c2-7d00bc346e50
I've been making progress little by little, but the left shoulder joint is taking more time than I expected 💦.
I followed the structure of the right shoulder, but I wanted to make the left shoulder's clamshell-like outer shell attachable later, and I'm having trouble adjusting it properly.

Mechanic Zaku progress 7/26 | nan_koromaru21's Gunpla works