If you can't clean up the painted edge, you could always add a 1x3 piece of wood as molding. You can even carry it up to the ceiling to frame that wallpaper. I don't see that paint color in the wallpaper, or maybe it's a lighter version of the flower centers. Maybe stencil on a design using the darker color, or another color from the wallpaper to help tie it together. Then narrow floating shelves or vertical frames or something in the painted areas it you feel you need it. Maybe turn the bed around so the wallpaper is the headboard.

Thank you for posting the pic. Is it just open space opposite the chairs and a blank wall with the entry door? Any windows on that wall? Is that a table showing on the right of this pic, or a counter between living room and kitchen? My first thoughts are that those chairs must be pulled away from the wall and angled in some way, and somehow you need to find space for more seating. Could you angle them towards each other against the room divider, or is that a cupboard you need access to? Then you could turn the table 90 degrees, and place other seating facing the chairs. I'm liking the idea of picking up on colour from the green glass on the table, but I'm not sure how yet. I have a busy day ahead but I hope to check in later.

I wouldn't put any water under there because of potential mould issues (in fact, there looks like there's a bit of mould already -- is there?). You could tile the bottom of it and put a strip of LED lights under the glass. What did you have in mind when you initially thought of the idea?

A big bold painting brings serious flair, and can instantly change the vibe of any space. a painting can create a focal point with impact and add both color and dimension. Pick up a few of its colors in accessories, like pillows, to highlight the piece even more. Here's some suggestion for your wall you might like......to know more about my Art work and collections please visit my shop on Etsy website - https://www.etsy.com/shop/PooviArtGallery?ref=pr_shop_more