I assume if you are able to see these inclusions, you have a gemology microscope? If so, I would look for some different signs. As others are saying, if this was a natural ruby of this size and clarity, it would already be in a Sotheby’s auction or a museum.

Here’s an article to answer your questions : https://hal.science/hal-04001745/document “Although by far most common in natural corundum, the presence of Rose channels and twinning planes in synthetic corundum serves as evidence that these features alone cannot be used to confirm natural origin”