Maybe you tried biome finder to find how biomes is generated. But after installing a lot of mods, do you know how the world changed?
Let's try this mod, you can export the biome map in-game by using this command:
/exportbiomemap <radius> <scale> <player>
<radius> stands for the radius of the exported map. <scale> stands for the scale of the map.
<player> stands for the player who stands at the center of the exported map. And after the exporting, this player will receive the successful information.
For example, <player> stands at (1000, 64, -2000). And <scale>=4 means one pixel of the exported map stands for a 4 times 4 area in your world. If <radius> = 4000 at the same time, the exported map will be 2001 times 2001 pixels, which indicates the biomes from (-3000, 64, -6000) to (5000. 64. 2000).