Hey there @corgon, I hope you're doing well.
If you're using Samsung Messages and want to disable read receipts, go to: Samsung Messages>Menu>Settings>Chat settings>Send read receipt. (You may also find read receipt options for SMS/MMS in the "More settings>Text/Multimedia messages" menus.
If you're using Google's Android Messages, go to: Android Messages>Menu (or profile photo depending on your app version)>Messages settings>Chat features>Send read receipts.
