Yes, the Germans who invented hydromorphone and oxycodone which was and still called eukadol in Germany have never heard of it.
OxyContin, created by an American company, Purdue and licensed to European companies to make and sell in Europe, including Germany, weirdly not heard of by Germans.
And opioids not used for Covid-19, heart attacks or breathing problems? As has already been stated, they in fact are regularly.
I'm guessing the anecdotal crap you said was from talking to regular German citizens and not people in chronic pain, medical professionals like GP's or those in ER/A&E in hospitals, cause they most certainly will have heard of them.
Hydrocodone isn't prescribed in Europe, so if you brought that or brand names of it up like Vicodin then no one will have heard of it.