eMMC would be a better choice.
I don't see how it wouldn't work on the same QSPI that works reading/writing NOR Flash devices, the bus and interactions on it are pretty flexible.
Memory Mapped and Execute-In-Place probably aren't viable or desirable.
You'll have to own writing the drivers and doing the block management. Perhaps wire a device of interest to a NUCLEO-144 with QSPI pins exposed and see if you are comfortable with the mechanics of it.
Best to contact FAE assigned to your account directly. Chip level technical staff don't really participate here.
