When it’s been tore up from the floor up, then likely it’s going to be improved upon. Base boards at the floor with or without a base shoe mould. Anything taller than what was demoed out will cover that existing caulking/paint line and produce more efficient progress. Adding a chair rail moulding breaks up a flat plain wall and adds some sparkle. HOME DEPOT HAS THEM ALL!
Casing around the doors and windows give a new and updated visual. Add a cornice crown cap for elegance, on any budget. Plinth blocks make a super strong statement of “I’m running things”.
Stair skirting with finals atop the balusters, Craftsmen to Victorian any contemporary or vintage appearance is DIY possible.
Wainscot paneling with bead board and a chair rail border around a room has huge potentials for resale factors.

Base Board Moulding Case Mould Chair Rail Moulding Crown Moulding Fireplace Mantels

Windows can be changed out to a stool and apron casual look but highly visible to set the tone of design. Any of this is extremely DIY able. Some stain or paint and you did it.
Where the walls meet the ceilings a simple crown moulding here is the difference of blah and vavoom. We’ve seen this on TV home decorating shows, how crown moulding can make a dramatic difference in any room.
Fire place mantels from a paint grade rudimentary ledge, to a full wrap detailed stain grade hardwood, with rope moulding and recessed panels. Bringing that into lives almost to good to be true feeling that floods the living room.