It's about knowing and seeing the Father. You need a new pair of glasses.Conclusion is Exodus 3:14-15 isn't Jesus speaking. John 14:9 is about knowing the Father, not Jesus being the Father if that is what you're suggesting, which is not an orthodox Trinitarian belief.
John 14:9 Jesus said to him, Have I been with you such a long time and yet you have not known Me, Philip? He who has seen Me has seen the Father. And how do you say, Show us the Father?
That takes us back to John 6:46 that precludes the possibility that it's the Father appearing to anyone except Christ. @civic astutely mentioned that already.This is evident from the context where Jesus stated, "From now on" meaning, from that point going forward, they "know Him and have seen Him" in John 14:7. Therefore, when Jesus said "I have been with you all this time, and still you do not know Me? Anyone who has seen Me has seen the Father." It wasn't referring to actually seeing the Father in the visual sense, but in the figurative knowing and understanding. That's the common denominator here.
Conclusion: Jesus is the "I Am" OT God mentioned in Ex 3.John 6:46 is the same idea as above. Jesus understands the Father.
None of this suggests Jesus pre-existed in the way you suggest.