I’m thinking with that long snout it was a bottom feeder, digging under the lakebeds and riverbeds for burrowing creatures. That could explain the eyestalks, which would allow it to keep its eyes above the muck watching for predators while it foraged.
Or it could have been an ambush hunter, burying itself on the bottom like an octopus, with just the eyestalks exposed to watch for prey, and using the snout to reach up and snatch anything that swam close enough.
Looking at it with your analysis, it seems quite likely you’ve got it.