A4 Note Length Global Setting?

Is there a way to change the global sequencer note length from 1/16?

No, set it (the Len default) per pattern/track before programming/recording


Eventually copy your pattern settings on all patterns. Trig page parameters including LEN are saved with patterns. Copy/paste a reference pattern to all patterns.
Save as project you can use after.

You can also set a template pattern at the end of the project, copy it when you need…