I'm seeing this issue when trying to launch the game:

And these are the versions of the mods I have:

The full crash log is here: https://pastebin.com/YN1y01YC

I've redownloaded the Optifabric and Optifine files in case they were damaged, but that hasn't fixed the problem. Any advice appreciated. Thank you!

Please update optifabric to 1.13.16.

Don't know how I missed that! It's working fine now, thank you.