With the space/volume I see in the photos, I'd suggest that there's no point in looking for 'studio' ergonomics nor performance. That's not to say that nothing can be done, but some careful thought, careful planning and a careful budget can improve things. I'd start by accurately measuring the whole room, and making a plan view, giving all salient details such as doors and windows, and how they open, and ceiling height, plus any other features such as radiators and the like. A list of the principle elements of your system (screen, console, monitor speakers, Fx and other boxes, instruments...), with their dimensions, and maybe a rating from 1 to 10 on a 'this is used most often' scale.
A lot can be done with trestles and worktops, and shelving solutions, either wall-mounted, built-in or even made mobile on castors can be part of the picture. Is the room used for anything else (stored boxes, winter coats, vacuum cleaner...)..? There's a need for much thinking 'outside the box', and much compromise to be made, but it can be done. Don't throw money at it; it would be largely wasted.
Disclaimer : I would describe my take on these things as tending towards the 'minimalist'; I spent decades working in IT from a 1 sq metre desk, and my present 'pica-studio' takes up less than 1 cu. metre before my armchair. When I need a keyboard, or my guitars or bass, they're played on my lap. Ideal..? Maybe not. As good as Peter Gabriel's set-up..? Very far removed..! Adequate..? Yes, and by necessity, so it is what it is. One cuts one's coat according to one's cloth.
Hope this helps.