Did the Targaryen dynasty start with a bastard..?

Hear me out,
In George R.R. Martin’s book Fire & Blood: "It was said at court that Aegon spent ten nights with Rhaenys for every night he spent with Visenya.”
Despite spending most nights coupling with Rhaenys, they only produced 1 son.
King Aenys I Targaryen, son of Rhaenys Targaryen, is described as a physically frail and emotionally fragile (despite being Aegon I’s son).
In the same sentence: “On the nights that Aegon was not with her, Rhaenys surrounded herself with comely young men. It was rumored that she also entertained some in her bedchambers."
Targaryens are not usually described as “weak” despite their consanguinity.

ASSUMING the rumor was true… could the Targaryen dynasty have started whit a bastard?

Also, Maegor I Targaryen, son of Visenya Targaryen, is described as a tall, broad, and fearsomely strong man. Like his father.
We know Aegon spent his nights with Visenya, following Rhaenys’s death. Maegor might actually be his son.

I’m just assuming, don’t hate on me in the comments.