Unfortunately the B and M keyings are almost, but not quite a mirror image of each other. In your case you got lucky that your slot was tight enough to prevent the incorrect insertion. I saw a similar post over on hardforum where someone actually managed to insert a SSD upside down.
In theory the key B pinout supports "PCIe ×2, SATA, USB 2.0 and 3.0, audio, UIM, HSIC, SSIC, I2C and SMBus", while the key M pinout supports "PCIe ×4, SATA and SMBus ". In practice the two interfaces we care about for SSDs are PCIe and SATA.
In practice slots that only support Sata M.2 SSDs are usually B keyed, slots that only support PCIe are usually M keyed and slots that support both are also usually M keyed. PCIe M.2 SSDs are usually M keyed, while SATA M.2 SSDs are usually double notched to fit both B and M slots.
您的插槽是 B 键，这实际上意味着您需要一个 SATA M.2 SSD。原则上，B key 插槽可以支持 PCIe x2，但即使支持，它也对您没有帮助，因为大多数 PCIe M.2 SSD 都是 M keyed。
根据您发布的图片，您使用的旧型号是东芝THNSNJ256G8NU，它是SATA III SSD。根据您发布的图片，它使用“B+M”键边缘连接器。
这是“B+M”连接器的样子：
同时，您购买并计划更换的新产品是 NVMe SSD (Samsung Evo 970)。它使用“M”键连接器。
您应该检查的第一件事是您的笔记本电脑是否支持 NVMe SSD。许多笔记本电脑只允许使用 SATA SSD，只有 SATA III 接口。因此，即使您可以以某种方式将这个新 SSD 插入您的 M.2 插槽，它也可能根本无法工作。
根据您发布的型号，我找不到您笔记本电脑的完整规格。
对你来说最好的替代品就是这个。
更新：
在深入挖掘之后，我从MSI找到了这个文件，其中声明“M”键 SSD 只能在“M”键插槽中使用：
在同一个文档中更深入一点：
因此，根据您提供的型号，您有 2 个“B”键 SSD 插槽和 1 个“M”键 SSD 插槽。但是，所有三个插槽都只能使用 SATA III SSD。您根本无法使用 NVMe SSD。
所以你购买的那个（三星970 EVO Plus）是不能用的。
您有一个不兼容的驱动器并试图将其倒置插入！
不幸的是，M.2 是一团糟。理论上，M.2 支持一堆不同的键控，每个键控支持不同的接口组合。与 SSD 相关的两个键是键“B”和“M”。
Unfortunately the B and M keyings are almost, but not quite a mirror image of each other. In your case you got lucky that your slot was tight enough to prevent the incorrect insertion. I saw a similar post over on hardforum where someone actually managed to insert a SSD upside down.
In theory the key B pinout supports "PCIe ×2, SATA, USB 2.0 and 3.0, audio, UIM, HSIC, SSIC, I2C and SMBus", while the key M pinout supports "PCIe ×4, SATA and SMBus ". In practice the two interfaces we care about for SSDs are PCIe and SATA.
In practice slots that only support Sata M.2 SSDs are usually B keyed, slots that only support PCIe are usually M keyed and slots that support both are also usually M keyed. PCIe M.2 SSDs are usually M keyed, while SATA M.2 SSDs are usually double notched to fit both B and M slots.
您的插槽是 B 键，这实际上意味着您需要一个 SATA M.2 SSD。原则上，B key 插槽可以支持 PCIe x2，但即使支持，它也对您没有帮助，因为大多数 PCIe M.2 SSD 都是 M keyed。
三星 Evo 960 Plus 驱动器具有 PCIe Gen 3.0 x4、NVMe 1.3 接口。您的
Toshiba THNSNJ256G8NU驱动器具有 SATA 6.0 Gbps M.2 接口。您的替换驱动器将是三星 860 Evo。