I've found that even the $25 Japanese jerkbaits, which are supposed to suspend, actually sink or rise slowly, depending on water temp, and line type and size, but not fast enough to matter.
I've also found it's impossible for me to get a lure to suspend perfectly, so I settle for close. I get it to float really slowly, then paint it and top coat it, and hope the paint/top coat make it suspend in cold tap water in my float testing 5 gallon bucket.
Then I can use the type and size of line, and the size of both split rings and treble hooks, to get them to either sink slowly, or float slowly.
Worst case scenario, if the lure still floats once I'm finished making and rigging it, I'll add suspend dots/strips to the belly, or a little lead wire to the belly hook shank.
But I don't think the fish care if it sinks or rises, as long as it is a really slow movement. Dying baitfish aren't neutrally buoyant, either.