I was trying to use shaders with the origins mod through Optifine and Optifabric but whenever i try to launch Minecraft with both in the mods folder the game always crashes. they both work fine separately but I cant launch the game with both in the folder at the same time. any idea what's wrong with it?

I am encountering the same issue its not Fabric's API it is legitimately a confliction between Optifine and Origins. While I do not use it for shaders I used to use it for performance. Then I discovered Sodium and that is an amazing option for performance, and a good stop gap if your looking for flat performance until Optifabric becomes available.