Time-Travel

-Fixed a small mistake compared to 1.3.1 wherein the backend for flywheel was set to 'Instancing' instead of 'batching' by default causing detrimantal performance loss for amd gpu's

If youre using an AMD GPU simply leave the settings as are. If youre using an Nvidia GPU enabling the flywheel instancing rendering very likely will improve your FPS. To do this change it in the configs or do "/flywheel backend instancing"

Also make sure to adjust the cores for the Chunk Update Threads in the 'Performace' tab in the video settings. By default this is set to 14 Threads. From experience setting this as high as possible improves framerates especially if they're already bad

Do not enable any kind of Entity Culling in the Video settings as this will make Create Contraptions freak out. Entity Culling is already provided by the Entity Culling mod which provides a superior implementation to the entity culling found in the Sodium Video settings menu

Recommended Java Arguments:

-XX:+UseG1GC -Xmx8G -Xms8G -Dsun.rmi.dgc.server.gcInterval=600000 -XX:+UnlockExperimentalVMOptions -XX:+DisableExplicitGC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32

You can also try running a different Java Virtual Machine. From experience OpenJDK/OJ9 doesnt improve framerates. GraalVM however may improve framerates ever so slightly. YMMV