Analysis of information sources in references of the Wikipedia article "Fugitive Doctor" in English language version.
I'll refrain from delving too deeply into what Jo Martin's "Impossible Doctor" means
The Timeless Child became an agent for "The Division," the Time Lord C.I.A. basically, and it was during this period of time that the Doctor was Ruth and hid on Earth and all that.
Ruth and Lee, are in fact another Doctor and her companion
she is definitively the Doctor
she had a past regeneration she couldn't remember
Ruth and Lee Clayton are two Time Lords
Lee had been her companion