May i ask where you got that info about the 4ml from since i never heard anything like that in any forum?
If our German Customs will open it, which so far in my experience rarely happens i think the bigger problem would be that it is a clone without any CE-Certification, german instruction manual and that stuff. How often this happens nobody will be able to say, especially when from the 1.7.2021 on the the 22€ importtax exemption gets removed, which leaves them with tons of more work to do.