iOS 11 throttled my phone so badly that I all but stopped using it. I'm not kidding. 11.3 unthrottled it, but by now I'm in the habit of not touching my phone. Finally got around to deleting my Facebook too (not because of the recent news; I was going to do it a while ago).
Total screen time is down massively. I pretty much only respond to messages on my computer, leftover from when keyboard lag made it tough on my phone, and it's never been a practical issue so far because the general talking via text messages was never important. E.g. I visit my girlfriend more instead of messaging her, similarly with friends. It's great. I feel way more relaxed.
Great to hear!