Find your container with "diskutil info / | grep 'APFS Container'" (mine is disk3), then run "sudo diskutil apfs addVolume disk3 APFS Models". The new volume shares free space with your main disk, so there's no partitioning and it's instant.
Exclude it in System Settings > Time Machine > Options > Exclude from Backups > + > Models. Time Machine doesn't snapshot a volume it doesn't back up.
Quit Ollama and LM Studio. Then move each model folder and leave a symlink behind, so apps keep their old paths: "rsync -aH --checksum ~/.ollama/models/ /Volumes/Models/ollama/ && rm -rf ~/.ollama/models && ln -s /Volumes/Models/ollama ~/.ollama/models"
Repeat for ~/.cache/huggingface, ~/.lmstudio, ~/models, and anywhere else yours live. It's a real copy, not a rename, at about 1 GB/s on an M5 Max.
Finally, free what the snapshots were holding: "sudo tmutil deletelocalsnapshots /"