I have this map system in our game, players check which map to play and in the next scene a terrain prefab is spawned accordingly.
Problem: I used to have 110+ FPS (with V-Sync disabled), but now FPS won't go above 20, I used trial and error to find out the culprit and it is the terrain, once disabled in playmode, FPS shoots up to it's old result.
What I tried:
- Baking lighting.
- Lowering terrain details density, count, you name it.
- Lowering terrain width/length/detail resolution per patch/detail resolution etc.
- Disabled realtime GI, baked the scene and still.
- Disabling shadows everywhere.
- Restarting unity and PC.
- As per comments I attached a screenshot of profiling

Note that FPS was 100+ with all above features at high values. Also note that I didn't upgrade unity to another version, am having low FPS on same device/unity version and day that I had high FPS on !!
What do you think happened ?
What else do you think I should try ?
Thank you!