Beware: Those MTD-Stuff does NOT work with consumer stuff. Highend-MTD is practically not existing for consumers because Windows doesn’t support them anyway.
If you check the Linux Kernel Frontend you’ll find a section about “MTD devices”. There are some userspace programs listed for managing the kernel components. Those tools are somewhat good for Host Based SMR hard drives but you might need tools to unlock the drives which I didn’t need because they got unlocked at work. Those HDs are only sold to data centers. The two I have at home are from work and it is a miracle they let me have them at all.
Flash based MTD though is sometimes available but not in normal computing. Because SATA, NVMe, eMMC are actually “to advanced” for that stuff. MTD is VERY Low-Level. The driver does everything, buffering, moving from MLC to QLC, refreshing cells and so on. For me it is a PCIE-Card with absolutely no intelligence but a very fat driver. But you might also find it in old Linux/Android-Based phones, Netbooks and Tablets though current smart phones use “smarter” storage like eMMC. Iphones have MTD but you can not get Linux to run on them.