Yes, you can use advanced features of Gather by Name to specify an item that should be the focus of the rotation.
{mythrite ore}
mythrite ore
crystal
*
Multiple rotations for different items are not supported, because this usually leads to GP pool being constantly depleted and not effective for gathering hidden items.
Is it also possible to tell miqo to use Quick synthesis?
At the moment Miqobot does not support Quick Synthesis. It’s one of the improvements that will be implemented in the future.
In the meantime, you can use “Ignore Quality” setting of the Crafting Solver. It’s slower than Quick Synthesis but it achieves the same result.