Hi! So I’m not Mr. Kate but I saw your comment and I wanted to help.
I think that Instagram and Pinterest are great for finding inspiration, but your room is reflection of your personality so you shouldn’t copy too much.
I also think that spray painting your cabinet yellow would really brighten up your room considering that the rest of the furniture is white. I also think that white walls can get kind of boring so doing a fun accent wall or putting big peace of art with blue tones or (even better, purple) would be contrast to your yellow cabinet. When you tackle the big projects you can have fun with accessories (you can add a few plants, decorations or even some bigger peaces like an armchair… you can add some interesting light fixtures etc.) that are going to bring personality to your room. This is going to give you a bit playful and colorful look.
For the second solution (where you spray paint/paint your cabinet metal) I think you kind of have to know what you’re doing because when spray painting (in general) you have to be careful not to get to close to the cabinet/object because you can get those weird dots of paint that are especially visible when spray painting with metal spray paint and dark spray paint, but in my opinion is that if you can find metal contact paper that would be cool (then just watch for the bubbles). If you want to paint your cabinet metal you can play with accessories from different metals and maybe paint/or put dark blue wallpaper with some geometric shapes. This is going to give you modern and industrial look.
I hope I helped you and I hope that Mr. Kate will agree with me. I wish you best of luck and a fun project with a beautiful room as an outcome.