I know it's a popular pastime for some, to rubbish most things, ( same folk who think Vikings had horns on their helmets ), but is it not true that every one of our ancestors are 'mythical', until they have been named and verified, with documentary proofs. We know they existed, otherwise we would not be here, but the proof is the catch. Even then, some things are questionable. I have seen members on Wikitree who claim descent from biblical figures, documented in a sense, but unproven just the same.
I would suggest that these characters be placed in a special catagory, ' Pending, awaiting verification ', not simply dismissed out of hand. Then, if a member can produce convincing evidence to support their claim, all well and good.
As historians, one thing we should have learned is that things called false or impossible by 'experts' in the past, have since had to be reviewed. Alternatively, we could bury our heads in the sand, and pretend that humanity did not exist before 1000.