My relative's device was controlled by an Arduino so indeed that was easier to trust. The untrustworthy Chinese components were more actuators, pumps, and so on

My relative's device was controlled by an Arduino so indeed that was easier to trust. The untrustworthy Chinese components were more actuators, pumps, and so on, so easier to test than an MCU. One advice concerning EMI is that it's one thing to certify the finished design, but it's tricky to design it right if you're not experienced with EMI. Before testing it's worth having some advice and design review with the specialists to see if they think the tests will pass and how to improve it.