I'm not sure fatigue is the right term in this case, since it typically refers to either a medical condition or wear and tear of machine parts and such.

I've found numerous examples of a stress-free work environment. Maybe that will help you get around the fatigue thing.

here one example:

Linde Material Handling NAMan and machine in harmony. Encountering the new Linde 39X for the first time ... costs and providing the operator with a stress-free working environment. ...
www.lmh-na.com/39xinformation.htm

This dictionary says:

er·go·nom·ics (ûr'gə-nŏm'ĭks) Pronunciation Key
n.

1. (used with a sing. verb) The applied science of equipment design, as for the workplace, intended to maximize productivity by reducing operator fatigue and discomfort. Also called biotechnology, human engineering, human factors engineering.

So, while you could expand, like you have done, and talk of reducing fatigue, but maybe you could go in a different direction with something like

XXX (company name) Hightech provides you with the ultimate ergonomic workplace

My guess from the USA.

Assuming that the operator can work "ermüdungsfrei".

OK, I know a pun may not be what you're looking for, but something like "You/your staff will never tire of working with an XXX machine" might just do the trick

I suggest you hinge the phrase around "operation" and / or "tiring", but leave "operator" out.

Lots of of examples, many are in Corporatebrochurese & Patentian dialects, which seem to me the real target languages.

It seems to me that it's meant as a catchphrase, so I feel 'beat fatigue with ...' is appropriate.