In case you didn’t know, you can customize the color of every part of the HUD by going into Accessibility > Color Blindness > Customize UI Color.
By changing the Friendly UI color to whatever you want, the on-fire color also changes. It looks really awesome and I’m sure the color you pick is awesome as well.
The drawback however, is this affects the colors of the friendly scoreboard, some hero aesthetics like Widowmaker while scoped, friendly text, and ability cooldowns.
While I understand that it changes all things relating to Friendly UI, it’s that there isn’t a second option to customize only the name plate and hero border.