Most people respond quickly to me, so if I respond quickly, I generate the endless back and forth of email. When this doesn’t necessarily show it, I know that when I slow down, there’s less email coming back my way.
The feature I want most from my email client/service: delayed send. That way I can write replies, get them out of my head, but not have them sent until the time I specify.
I pay $5/month for boomerang for gmail (they have for outlook too?). I mostly use it to have messages that don’t get responded to come to my inbox (for follow-up) but it also has a “send later” function. Sounds like what you want!