I had issues with OMV 4.x install due to incompatability between my mobo and vanilla stretch. I needed to do an inplace upgrade from 8 to 9 and install kernel upgrades before reobooting to get around an issue similar to yours. Have a look at the in-place 9 to 10 Debian upgrade guide:
Take note of section 4.6 that talks about upgrading your kernel.
(Don't try this on your live build - swap in a blank drive to test out a fresh install Stretch followed by an in-place Buster upgrade with kernel upgrades. Once this is sorted, you can install OMV on a stable OS.)