Suggestion - Scheduled Night Time
A thought I had, a scheduled night time setting within SwiftKey where at a set time at night between say 8pm & 6am where a dark theme is automatically applied and vibration is disabled?
Would work wonders for bed time.
Then come morning light theme applies and vibration re-enabled.
See also https://support.swiftkey.com/hc/en-us/community/posts/115003751505--Feature-request-Auto-day-night-mode?page=1#community_comment_360004019731