Organizing messages manually or creating filter also increases our stress level.
In email, organizing the messages is handled by receiver. If the messages are organized by the time when you open your inbox that will save your time and take you closer to stress level zero.
Formal Messenger ( https://www.formalapp.com ) organizes the incoming messages with help from senders. So your inbox will be organized by the time you open it.
Formal is a email alternative app like Slack but for external communication.
Along with 4 rules you shared here Formal may help you to keep your stress level low.
Disclosure: I am a developer at Formal.