How do i render a custom texture on the Sun, only when im in a specific biome?

I have a mod where i want to use a custom texture on the sun, but only when the player is in the biome i made. none of these plugins are helpful because ive already spent too much time on this mod on the 2025.3, and it just will not downgrade to 2024, ive tried literally everything, and then right when it was building, it had to skip every single element that i made. so safe to say plugins arent an option, at least not the 2024 ones. does anyone know what to do? im really bad at java, and i have no idea what else to do.