The Tetragammaton is Hebrew. Jesus spoke Aramaic. He is quoted by Mark in Greek ("[symbol]]Egw Eimi[/symbol]"). So we don’t know what his actual Aramaic words were. If he uttered the Hebrew Tetragammaton, Mark doesn’t tell us that. It’s a clever interpretation but I don’t think it holds water. People had to say “I am…” for mundane reasons, and I doubt that the Aramiac construction was the same as the Tertragammaton. I know nothing of Aramaic, though, so I can’t say that for sure (but I would be surprised).
The quotation from John indeed sounds like it could be a claim to Godhood, (and John in his intro identifies Jesus as the Logos who was “with God” from the beginning. I have to point out, though, that it is not entirely clear wht John meant by “Logos,” other than he seems to have a different interpretation of it than Philo (who introduced into Judaism from Greek philosophy), and that there is no previous identification of the Logos as identical with God either in Greek phiolosphy or in Judaism (nor was the Logos ever personified before John). Prevous conceptions of the Logos were either of the will of God or (as Philo argues by extension) a divine mediating force between God and man.
Be all that as it may, I will save my argument against the historicity of Jesus’ “I am” speech in John (to put it bluntly, I just don’t think Jesus said it), and simply point out that while John has the most self-aggrandizing Jesus, he does not have a Sanhedrin trial. John just has Jesus briefly questioned by the priests and then turned over to Pilate (a possibility which I have already stated that I find more plausible than Mark’s trial). So while it might be argued that Jesus’ words (if he said them) might have been perceived as blasphemous, John does not have Jesus convicted of it. And Mark has the high priest saying to the rest of the Sanhedrin, “you have heard the blasphemy,” which they hadn’t if it was supposed to be some sort of allusion to the “I am” speech (and which Mark has told us nothing about).
Because John and the synoptics have different and contradictory Passions, it doesn’t really help to conflate them.