Comment by grapheneos

Samsung does have MTE on certain devices. They don't allow us to support their devices by either not allowing another OS or crippling functionality including security for them. Samsung has nearly all of our security requirements on certain devices but that doesn't mean we can support them. Samsung also does decent updates for the drivers and firmware on their flagships too. Samsung is welcome to work with us and have GrapheneOS support for their devices.

GrapheneOS supports 'a' series Pixels and those provide the same security and updates as the higher end devices. A used Pixel 8a is a very affordable device with great overall security nearly as good as a Pixel 10 and plenty of update support remaining. Pixels are not available in enough countries but the 'a' series devices combined with the long support they receive already provides very affordable devices in countries where they've been available for years.

Qualcomm was quite late to providing MTE due to their custom cores. Snapdragon 8 Elite Gen 5 does provide MTE, as will the next generation SoC used on the initial Motorola phone with GrapheneOS support.