You have to use SNAP for that. That means you need to connect to the remote NVMe-oF target via SPDK, and then export the block device with NVMe emulation.
As for
Additional information, I know that with the BlueField controller HCA, I can access the SSD on the host from BlueField2. But is it possible in reverse?
This depends on what you mean by “access.” For some reason, I suspect you mean via PCIe, because the other access method is just with NVMe-oF, which you are already doing. If you do mean by PCIe, then the answer is no for both. The BF2 cannot access the host SSD via PCIe.