Thanks @EricSerdahl the sealed air chamber is a good suggestion. I thought of it earlier on but discarded for various reasons, but may pay off to revisit the concept.
Thank you for the detailed suggestion with the bolt and magnet. My current solution, that works pretty well is a reed switch encased in the epoxy, using a neodymium magnet when shipping the product to keep it switched off. However, I don’t have a good housing for the magnet as pictured in your bolt solution.
Unfortunately my various push button/rocker switch experiments failed to deliver a viable option.