Since you’re wanting just a temporary fix, perhaps just one roll of vinyl peel and stick wallpaper in a pattern that can be laid horizontally. It would protect your drywall until you find what you want.

Life happens. I wouldn't waste time or money on a temporary cover up. Your guests won't judge that you have an unfinished backsplash due to a contractor's mistake. We have all been there!

Paint and a fun piece of art like a poster .

Krylon white spray paint.

Quick spackle skim coat and paint it the wall color.

A slab splash there will be awful and oppressive. You need to do something more permanant, and a better design. For a bar area, something sparkly and interesting would be better than dim and dark. Marazzi Geometal has a lot of interesting shapes, and would work to bring in an upscale bar like look.

If you have a large piece of stained glass you can hang it there or peel and stick that you can remove for the construction work to begin that would be really nice it look like a backsplash or if you don't want peel and stick it's supposed to not leave anything behind you think it's too tacky looking you can put up a pretty sheet metal just lean it on the wall and if people comment say you're waiting for the construction to begin or your tile to be replaced

Mirrored backsplash for bar area.

Mirrors with bars kind of go hand in hand.

Love the idea of mirrors! Any idea how to create the patchwork mirror look in the last picture?

Quickest fix would likely be to just patch up the damage to the drywall and paint. That would get you by while you look for a backsplash you love.

Agree^^^

Then when you are ready to look for tiles that much will be done.