I have done the math and I think we have all been celebrating the Seder nights at the wrong time! If we travel back 3335 years to the first Seder night during the exodus year (in 2448), we were not yet actually free. At that point, we were still in bondage.
We were freed after Makat Bechorot - the plague of the firstborns, i.e. right after חצות - midnight, which also happens to be the exact time we are particular to finish the core of our Seder by. We actually only left at dawn, at which time even the five great Tannaim we read about in the Haggadah, finished discussing Yetziat Mitzrayim - the exodus from Egypt.
This seems paradoxical, at the Seder we are obligated to lean and drink four cups of wine to demonstrate חירות - freedom. Meanwhile at this time during the actual liberation year, we hadn’t left Egypt yet and weren’t even freed yet. We were only allowed to leave after midnight and actually left the next morning. If we are celebrating while we are still slaves, aren’t we celebrating prematurely? This would be like Americans celebrating their victory over the British (😉) on the 3rd of July rather than the 4th when actually declared independence!?
The profound message we learn (based on the Maharal) is the reality that all transformations happen before we see them. In other words, Hashem is orchestrating everything behind the scenes, and by the time we humans see it, it has already happened in the spiritual realm. This was also the message of Purim, where even though no overt miracles occurred, we carefully read the Megillah and realized that despite it never mentioning the name of Hashem, the Creator was behind the scenes orchestrating the salvation long before Haman's appointment.
Similarly, over Pesach we learn that even with the many open nissim (miracles) the spiritual reality remains that Hashem arranges the transformation long before we saw it happen. More importantly, in the hours leading up to them being freed, our ancestors were prepared spiritually for the nissim that were about to occur, meaning that already that night, before formally being freed they were בני חורין - a free people. (In Kabbalah this is called אתערותא דלתתא - once we have prepared ourselves down here, we become receptive to divine intervention from above). In a similar vein, on Seder night we don’t wait for Eliyahu Hanavi - Elijah the Prophet to come to us… we open the door for him (or at least most do)!
A nation that had been enslaved for 210 years had, at Hashems’s request, taken the Egyptian idol, tied it to their bedposts for days before then slaughtering it and putting the blood publicly on their doorposts. At that point already they were worthy (to a certain extent at least) of being redeemed and that is why we hold our seder then.
Moreover, if the seder were after the redemption, it would be merely a commemorative occasion when, in fact, it’s the opposite. We are instructed to relive leaving Egypt, not just to simply acknowledge it - as we say at the end of the Haggadah from the Mishna in Pesachim (10:5) ‘בכל דור ודור חייב אדם לראות את עצמו כאילו הוא יצא ממצרים’ - ‘In every generation, one must see oneself as though they personally left Egypt’. What we are really doing is re-enacting the experience, one which will hopefully give us inspiration for the entire year.
Wishing you all a Pesach Kosher V’Sameach - a Kosher and joyous Passover!