true, though the pharisees were likely thinking what actions were needed, things that they could do, that others can see etc., whereas Jesus replied in essence that the most important thing is first & foremost to believe in the one God sent, so to recognize & believe in Him.
So it could be that what Jesus was referring to was that they should study and understand their scripture & its prophecies so that they could recognize the messiah when he came and then believe in him. That's how they would believe in Him.
So the most important work was to know their their scripture as it pointed to Him. Definitely room for discussion but I can see why you might say faith = works = faith from that even though later Paul clearly distinguishes faith from works.
That particular passage,
John 6:28-29,is frequently misapplied.
So many covenant theologians use it out of its context. They read Paul's mystery grace revelation into it when that was not the intention of what Jesus was saying above.
John wrote his gospel as a record of the 8 signs that Jesus performed in order for Jews to believe that he is their promised Messiah (
John 20:30-31).
In that record,
the signs are seen as works of God. There are at least two times the John account explains that.
John 10:
24 Then came the Jews round about him, and said unto him, How long dost thou make us to doubt? If thou be the Christ, tell us plainly. 25 Jesus answered them, I told you, and ye believed not:
the works that I do in my Father's name, they bear witness of me.
John 14
10 Believest thou not that I am in the Father, and the Father in me? the words that I speak unto you I speak not of myself: but the Father that dwelleth in me, he doeth the works. 11
Believe me that I am in the Father, and the Father in me: or else believe me for the very works' sake. 12 Verily, verily, I say unto you, He that believeth on me, the works that I do shall he do also; and greater works than these shall he do; because I go unto my Father.
Once you understand what John was trying to do in his gospel, this verse you quoted is not saying CTs are trying to make it say, after they read Paul's revelation of the mystery.
Jesus was not saying, in ,
John 6:28-29, to "believe in his death burial and resurrection and that is all you need to do to be saved."
He was telling the Jews to believe in the signs, that he is their promised Messiah. The Jews, and Jesus were always under the Law of Moses pre-cruxifiction, and that Law must still be kept.