How to turn off sent sound effect on imessage

I want to silence the noise my iOS 17 iPhone makes when sending an iMessage - especially when in Sleep Focus Mode. Nothing seems to work.

1 Some suggest disabling Sent Mail in Sounds & Haptics. Doesn’t work.

2 Don’t want to disable any iMessage Notification Sounds as that will stop incoming messages no matter what focus is selected

3 Only thing that works is Silent mode enabled by the side switch - which isn’t automatic. Cant find any way to enable full Silent mode based on a Focus mode

Seems like a corner case that slips through apples numerous and complex notifications and focus mode options.

any ideas?