If you could go into more detail on the CE self certification that would be awesome. How did you figure out what testing you need to perform on the product to complete the self certification? The biggest source of confusion for me is this aspect of it. Sure I can self certify that all is good, but how can I be certain that I am not missing something that will get me into legal trouble?

For my own project the biggest source of compliance is related to the ESP-32 that I am using (because of the WiFi/Bluetooth radio). Of course the boards I get from Amazon and Alibaba all have CE written on them, but how can I trust that? I read that the seller has to give CE certificates but they always seem to have a serial number that appears fake (there was some database that you can look them up in and they always fail to show up). I also read that putting together components that are all CE does not mean that the full product can be considered compliant. So in general it seems like a massive undertaking.