30 years ago I had a very relaxing 3 years doing a PhD (in math) and got a 30% boost in salary in my first job due to having a PhD. I enjoyed it enormously and had many enjoyable summer holidays and plenty of time to row crew.
But sadly I think that’s very much the exception rather than the rule nowadays, especially in the US (and outside of math I think it’s very hard to get a PhD without doing a lot of time consuming work). And from what I’ve seen in Silicon Valley a PhD can limit rather than expand your opportunities by pigeonholing you as an engineer rather than a manager.
So I’m not sure you could expect it to be either a particularly enjoyable experience or one that would benefit your career significantly (unless it’s in something that turns out to be hugely in demand - for example the CMU autonomous vehicle researchers have mostly done very well for themselves).