Heres what I would do, ymmv
Id take out that locker by the nav station and arrange a forward looking nav position, and I would relieve much of the bulkhead above it in ways discussed earlier
I would give up the berth aft starboard and make it into a locker under the cockpit seating. But I would keep 500-600mm of it for the galley, making the galley more U shaped.
The stove arrangement isnt right and takes up too much room, so make new cabinetry that is narrower giving more room in the U, and put the sink out there where the stove was where its closer to the centreline of the boat and put the stove where the sink is.
With the narrower cabinet and the foot space in the galley relieved of the step, you will have much more space to be able to be within the galley instead of outside it.
At the same time, Id relieve the galley bulkhead above the counter to make the eye level distances seem more spacious.
Assuming the bulkheads are structural, to remove much of the galley and nav bulkheads properly requires adequate framing to replace them. I would laminate a beam under the cabin
roof where the bulkhead was, and do the same under floor while allowing holes to cope with any possible bilgewater.
These problems the boat has make it near unlivable, but they are fixable and the price
of the boat is right provided there are few other issues. Typical homebuilder thing really, bound to be a few more like that.
Connect the underfloor and cabin roof beams with stout laminated columns on the cabin sides and in the thruway fasten mechanically and epoxy
One problem I can see in the images
is, there is no bridgedeck, If the cockpit takes water
its going to go straight down into the cabin. Also those cabin doors look near useless. You need to redesign that so it opens the other way
and covers the entire aperture to the cabin.