I think the fact that you can’t turn off read receipts is a kind of shady way to keep you using the app. You also can’t turn off notifications for a chat without going into it and notifying the participants you’ve read the message.
It absolutely is a "shady way to keep you using the app", in addition to a whole host of other subtle things you wouldn't even notice. My intern project one summer was a (failed, thankfully) experiment with one of the darkest patterns imaginable. Everything is very carefully tuned and measured against relevant stats. If it looks good in some place like Venezuela or Zimbabwe, it gets lined up for general rollout.
I'm not a big export on notifications, but afaik on current Android there's OS level ways to turn off notifications. Eg. in the swipe-down thing if I tap-and-hold a FB notification, it offers to turn off all notifications of this category (eg. FB comment notifications). I just tried it.