As the appearance of the garden has a modernist style with the straight lines and concrete furniture how about a Mondrian influence and add a bold strip of blue? It is a pond and with the right shade it could look really relaxed and contemporary. My daughter's suggestion is a chalky lilac!

Small all in one condo room not sure what color to use for walls after removing wallpaper

Textured linen or with a subtle print wont date. Feature walls make a room smaller as they jump out ar you. Wouldnt recommend. Get some interesting art or craft. Pick up colour with accesories

Is this picture taken during the day or at night? If it’s daytime your kitchen must not get much natural light. Go for white cabinets to reflect as much light as possible to brighten the room up. Boring but timeless & always looks fresh. For colour you could do a splash back, or just add colour via accessories such as a bright kettle/toaster set, tea towels etc., easier & cheaper to change if you get tired of it.