I agree with Diana, there isn't much you can do that will not involve more work than it is work. If you paint the wall a colour that is closer to the counter colour you won't notice it as much. Yellow is just about the worst colour for that counter and it isn't great with the cabinets either. Paint and wait!

IF....the counter fits tightly to the wall at the back, the tile option is do-able with good results as it appears to be a 2 piece installation. remember to use a sharp blade to cut the caulking to minimize damage to the wallboard. if you are doityourselfers you could even retile the entire backsplash inexpensively.....but, less is better if you want your new kitchen soon :)

choosing a tile wider than the existing 'step' is a must and one with a 'finished edge' will also minimize effort and maximize results

happy new year!

There may be some ripped drywall when you pull the 4" splash off. Paint it over with Zinsser Gardz to seal. You might need to fill in some spaces with spackle or a thin coat of drywall mud. You can just prime and paint then. The damage will till slightly show, but it will be clean.

You could as a temporary splash use wallpaper or paintable textured wallpaper - there is some that looks like beadboard and I used it in my basement kitchenette (In my "my pics" idea book.) There are stick on tiles that are supposed to be able to come off with the heat from a hair dryer. Do not use anything busy - busy backsplash do not work well with oak. The problem with the stick on is that they are more expensive than regular subway tile. You can do the subway tile, but when you go to redo the kitchen it will need to be removed and leave a damaged area to be repaired or replaced which might increase your remodel cost.