Any advice on turning guitar chords into piano chords? They sound very "off" on piano

I'll play a simple guitar song while singing that uses G-C-G-C-D chords, but if I try singing along with those same chords on the piano, it sounds way worse - the chords sound too far apart, way more basic, the singing doesn't "go" with it, and sounds very bubbly/poppy, almost like a children's song

Any advice on translating guitar chords to piano chords?