Outdoor PCB Self-Certification Support

We have a very low-power, 3.5VDC printed-circuit board (RPi5, Arduino, ESP32/STM32 based or similar) housed in a ATEX EX certified plastic enclosure (we just picked one from many vendors' products) that will be integrated into an item of industrial equipment and installed outdoors (temperature range about -10C to +55C). Before the first production run I need your help to self-certify the unit, also documenting that it meets all applicable ATEX EX Zone 2, C1 D2, safety and EMC requirements.

I will need a concise compliance file: test plan, test results or calculations, risk analysis, and the final Declaration of Conformity I can place on company letterhead that will be valid for use in hazardous environment.
Below link has some relevant info.
https://atex-iecex.com/atex-certification-process-step-by-step-guide/
Category 3 or similar

Please respond only if you can help& after fully reading & understanding. Provide some similar self-certify job examples. If you do not supply examples, we shall assume you have them & will supply us.
Please do not respond if you are not serious or cannot do this work. Do not use AI/BOTs to respond.
Our budget given is placeholder only, bid your best bid with time.
Any major issues must be addressed in 1st response to weed out fake responses.