Take your own advice. I believe all those Bible translators from Wycliffe to modern ones know/knew more than I, & I accept their use of 'as' in the verse in question. I also accept REALITY. Sammy Davis Jr. remained an African American with brown skin after he converted to Judaism, and Zora levitt remained a Jew after he became a Christian.
But no one MUST keep passover to be saved. That's the theme of this thread.
Where have you ever heard, in your entire life, that Sammy Davis Jr. wasn't a Jew the same as any other Jew? Nowhere, except maybe from a fellow Dispensationalist Christian who knows nothing about Jews. Who told you that there is any way that Sammy wasn't a Jew the same as any Israeli? If Sammy wanted to immigrate to the state of Israel, his citizenship as a Jew in that country was his to claim.
You tell me you believe all those authorities who translated the English Bible, yet you believe no authorities on what a Jew is.
Any authority of biblical Hebrew can tell you that the word "as" doesn't appear in Exodus 12:48. But, if a convert is to be counted AS as native of Israel, what's the difference between him and a native of Israel? If he's AS a native in regards to the promises to Jacob, then what does that do to your theology?
Galatians 3:29 And if ye be Christ's, then are ye Abraham's seed, and heirs according to the promise. (sorry, no "AS")
Dispensationalists do not believe the Bible. Period. Your doctrine has played a role in killing the western church (but, yet, the church will prevail over your doctrine).