It’s interesting to me that you say
And, if so, please, explain why they were as great as John the Baptist.
As though you are anticipating the answer to be yes? Of Samuel and of Samson it is not said as of John the Baptist
“For he will be great in the sight of the Lord; and he will drink no wine or liquor, and he will be filled with the Holy Spirit while yet in his mother's womb.”
Luke 1:15 NASB
In Samson’s case he lost his strength at one point but even so his strength was not always present with him. There is a certain phrase that keeps occurring with regards to his strength which seems to indicate that Samson was not continually under the influence of the Spirit of the Lord.
“And the Spirit of the LORD came upon him mightily”
Judges 15:14 NASB
As for Samuel, he receives his calling as a boy, maybe that means less than 13 and his children did not follow in his footsteps. While he is not responsible for his children’s actions it points out that Samuel did have a family. So he did have some cares of this world and providing for his family.
But John the Baptist was filled with the Spirit from the womb. So much so it affected his mother when the Spirit moved him.
“When Elizabeth heard Mary's greeting, the baby leaped in her womb; and Elizabeth was filled with the Holy Spirit.”
Luke 1:41 NASB.
It doesn’t say of John that he ever had a family but rather he seems to have committed himself fully to God and his prophetic ministry, not worried for his clothing nor even what he should eat.
“Now John himself had a garment of camel's hair and a leather belt around his waist; and his food was locusts and wild honey.”
Matthew 3:4 NASB
He didn’t seem to have any concern for the here and now.
“And if you are willing to accept it, John himself is Elijah who was to come.”
Matthew 11:14 NASB
Jesus identifies John with Elijah who was to come.
I know of no other man in scripture who was called from his mother’s womb and filled with the Spirit prior to birth. But further when he is of age and able to decide for himself forsakes even living in a house but dedicated himself completely to God.
Samson and Samuel are not on par with John the Baptist. He was in a separate league entirely.