It looks like every single new message sender creates a custom notification channel in the SMS app. Aside from making the notification settings a little crowded this isn't really a problem, but there doesn't seem to be a way to set the default behavior.
I'm asking because I want some apps to be able to display their full notification content on the lock screen (e.g. calendar and reminders). To do that, I need to set lock screen preferences to allow showing sensitive content, and then turning OFF sensitive content for apps where I want it hidden. This approach works for everything except the SMS app, since every new sender creates a new message channel, which defaults to "show all."
I don't really use SMS for anything except idiot banks that still use SMS for MFA. I obviously can change those channels specifically, but they tend to send from semi-random numbers that pop up differently for each new message (of course they do).
Has anyone figured out a workaround for this? I'm otherwise happy with the simple, default app since it's such a rarity that I need to use it for real communication.