The most physically tiring jobs I've done were events. Racking up a step count of 30k a day, easy.
However, the most grinding work mentally was a mid-level project manager role. Travelling to the four corners of the country, working on the train, working at the weekend, not being able to stop thinking about it on holiday.
And the worst work I've experienced was senior leadership during a crisis. I ended up signed off with stress, and never went back. I still feel the effects today of what was a period of six weeks.
I don't think any job level has a unique claim to working hard. I do think that like it or lump it, if all you have to sell is your PHYSICAL ability to work, then yeah, you're offering the lowest common denominator.
What I sell my hours on is my ability to knock 10% off an operational budget or spend 25% less time on admin. That is innately more valuable to most organisations.
But I'm not going to claim I work hard. I've been there, done that, and the most enjoyable of the three listed above was the events work.