It doesn't work with the code to bind the buttons to the following Views.

Problem was mainly how ForEach and NavigationLink where intertwined : https://stackoverflow.com/questions/66017531/swiftui-navigationlink-bug-swiftui-encountered-an-issue-when-pushing-anavigatio/67626758#67626758

Here is a code that works (even though some error messages I had no time to clear):

struct Item: Identifiable, Hashable {
    var id = UUID()
    var name: String
    var color: Color
    var image: String
}
    
struct ContentView: View {
    
    @State var navigatedItem: String?
    @State var isActivated = false

    @ViewBuilder
    private func selectedView(name: String) -> some View {
        switch name {
            case "Medical": MedicalView()
            case "Illness": IllnessView()
            case "Vaccune": VaccuneView()
            case "Dewor":  DeworView()
            case "Allergie": AllergieView()
            default: EmptyView()
        }
    }

    var body: some View {
        
        NavigationView {
            ZStack(){
                Color(.systemGray6).ignoresSafeArea()

                VStack() {
                    ScrollView(.horizontal, showsIndicators: false) {
                        HStack(spacing: 5) {
                            ForEach(MockData.items, id:\.self) { item in
                                ZStack {
                                    Button(action:{
                                        navigatedItem = item.name
                                        isActivated = true
                                        print(item.name)
                                    })
                                    {
                                        RoundedRectangle(cornerRadius: 10)
                                            .foregroundStyle(item.color.self)
                                            .frame(width: 70, height: 70)
                                    }
                                    
                                    Image(systemName: item.image)
                                        .foregroundColor(.white)
                                        .font(.system(size: 30))
                                        .padding(20)
                                }
                                
                            }
                            .background(){
                                NavigationLink(destination: selectedView(name: navigatedItem ?? "Medical"), isActive: $isActivated)
                                { EmptyView() }

                            }
                            
                        }   //HStack
                        
                        //opciones
                    } //  cierre scrollview
                    
                    .padding(.top, 20)
                    .padding(.leading)
                    Spacer()
                }   //cierre Vstack
                
            } //cierre de Zstack
            .navigationTitle("Caracteristicas")
            
            .toolbar{
                ToolbarItem(placement: .navigationBarLeading)
                {
                    Button(action:{},
                           label: {
                        Image(systemName: "switch.2")})
                }
                
                ToolbarItem(placement: .navigationBarTrailing)
                {
                    Button(action:{},
                           label: {Image(systemName: "person.circle")})
                }
                
            }//toolBar
            
            .accentColor(.red)
            
        }
        
    }
}


struct MockData {
    static var items = [
        Item3(name: "Medical" ,color: .red, image:"heart"),
        Item3(name: "Illness" ,color: .blue, image:"pill"), // Illness
        Item3( name:"Vaccune" ,color: .orange, image: "syringe"),
        Item3(name: "Dewor" ,color: .green, image: "microbe"),
        Item3(name: "Allergie" ,color:.purple, image: "allergens")]
    
}


struct MedicalView: View {
    
    var body: some View {
        Text("Medical")
    }
}

struct IllnessView: View {
    
    var body: some View {
        Text("Illness")
    }
}

struct VaccuneView: View {
    
    var body: some View {
        Text("Vaccune")
    }
}

struct DeworView: View {
    
    var body: some View {
        Text("Dewor")
    }
}

struct AllergieView: View {
    
    var body: some View {
        Text("Allergie")
    }
}