As a Brit, I don't think you will encounter any difficulty entering United States.
I went into the US twice this year, received "random" secondary screening both times, but my laptop never left my sight, and they've never asked me anything about my online activity.
Of course, I would still advise everyone to prepare themselves in case it does happen. I personally followed EFF's recommendations that they gave during 34C3: https://media.ccc.de/v/34c3-9086-protecting_your_privacy_at_...
https://nakedsecurity.sophos.com/2018/04/04/hand-over-your-s...
I've got no beef with US immigration other than hearing repeated horror stories over the years from moderately reputable sources.