Yes, it seems VERY appropriate.
If this went viral - especially if included in protests - it could provide a united voice.
It truly is only the God of Heaven who can save us now, and publicly calling on Him as our only Help would be a good step.
After a little research at the suggestion of yourself and others, based on descriptions, significance, and history (Washington’s cruiser flag), I’m opting to display An Appeal to Heaven Flag!
It definitely fulfills my needs, and says exactly what I want to say.
I think it’s perfect ~