The OP does not mention the name of one VW exec (Oliver Schmidt, the head of VW's environmental and engineering office in Michigan, a German citizen) convicted in US Federal Court in 2017 for his part in the scandal. He was released after serving about 3.5 years in prison.
A second exec sentenced in the US (also in 2017) was James Liang, also a German citizen, who prosecutors say "was a pivotal figure in designing the systems used to make Volkswagen diesels appear to comply with U.S. pollution standards, when instead they could emit up to 40 times the allowed levels of smog-forming compounds in normal driving." He cooperated with prosecutors and was released from prison in 2019.
I vaguely remember that the top execs were charged by US (Federal) prosecutors (in 2017) but the German government refused to extradict. Schmidt was arrested and tried only because he made the mistake of traveling to the US after the scandal came to light (although of course the German Court might have gotten around to trying him like they tried the execs in this current news story).
Deutsche Welle has a bit more detail and also discusses the CEO:
https://www.dw.com/en/4-ex-vw-managers-guilty-of-fraud-over-...
Apparently he has some health issues which caused the case against him to be suspended. That might resume later but unclear right now. He's 78 at this point.
The VX emission cheating scandal came to light a decade ago in 2015. If a 78 year old is too old to prosecute, Germany should have prosecuted him a decade ago when he was 68.
Instead, Germany refused to extradite him to the US to stand trial in 2017 [1].
[1] https://www.justice.gov/archives/opa/pr/former-ceo-volkswage...
Many countries do not legally permit the extradition of their own citizens. In Germany, extradition is generally only allowed to other EU countries, which meant the German government’s options were quite limited.