Totally agree, can't tell you the times I have listened to some saying why don't you go darker, each time a disaster, all I get is a muddy look that takes away the shine.
Always best to get a hairdressers advice, though I keep my highlights with Belle Blonde Natural Extra Light Blonde, and use Schwarzkopf Gliss Spray Shine. For years I Uses "Touch of Silver" Spray shine, but it has been discontinued now I have never found one as good as it.