Nebula theme icons are default?

I own a roku tv TCL model 40FS3750 and recently changed my theme to Nebula. The icons were tied to their theme i.e. hdmi cable and port instead of just port. I had to factory reset because younger siblings downloaded almost every game on the tv so I decided to reset. I put on the Nebula theme and the icons reset to normal? How do i fix this? (i tried factory resetting again and it did not work)