A German news site reached out to Verbatim about this and got the response that the discs are still M-Discs and will still last 1,000 years: https://www.heise.de/news/Langzeitarchivierung-Verwirrung-um...

> Verbatim clarified that these discs were advancements. The technical changes resulted in a different appearance and the ability for higher burning speeds, the changed media-ID was due to an adaptation with regard to other Verbatim products. Verbatim had already shipped the first modified media in early 2022. The data security of the new discs is not inferior to that of the old discs: Data should also last 1000 years, according to the manufacturer.

I'm not sure what you mean by "Verbatim just slaps their brand on other people's discs". Verbatim used to be owned by Mitsubishi Chemical Media, and was sold to CMC Magnetics in 2020. The only two manufacturers I see on that page for Verbatim discs are Mitsubishi Chemical Media and CMC Magnetics.