I am wondering if words like "Zen" are alienating for western audience. Do people think this is some kind of religious thing, or are they open to it?
Some of the people will have a fuzzy picture revolving around East Asia, monks and meditation. Only a very small fraction will have deeper knowledge about this topic like koans and zazen.
So depending on your target audience, using "Zen" for marketing might not be very useful, unless you're planning to play with the more common (but less accurate) connotations.
Westerners (especially Americans) tend to interpret them through a very narrow Abrahamic lens that severely impacts their understanding.