How can I make the ion-button icons the same size as the ion-menu-button icon

I’m trying to make my app consistent. I have to use a button to display the menu icon on a particular page instead of the usual ion-menu-button because I have two menus and ion-menu-button doesn’t support that. However the icon ‘menu-outline’ is displayed much smaller for no apparent reason. I have tried different fonts with !important, but I can’t make them all consistent.

Is this a ‘feature’?