I'm not clear what you're asking -- what exactly do you need help with? (ideas for what?)

If you are worried that stuff will fall behind the washer/dryer, attach a foamcore board to the side, as tall as the washer/dryer. Six or eight inches width may be enough. It's okay to use removable white painter's tape to attach the foamcore. White duct tape makes a sticky mess when you try to remove it.

Looking for ideas to camouflage the gab between the wall and dryer. TIA

For good camouflage, have a wood board cut to fit the gap, paint it to match the wall or the washer/dryer, then slide it into place and attach it to the wall. The key features are matching paint colors and making it easy to remove for washer/dryer service.

Creative way to hide the gap between the washer/dryer and the wall.

No one is going to stick their head to the wall to see the gap.