prototype00
Explorer
What is there to debate? It takes a single Magic Action to cast Find Familiar, and that Magic Action requires you to maintain concentration while continuing to take the Magic Action for 60 minutes.
Per the definition in the rules glossary on pg 371 of the 2024 PhB, if you want to cast a spell with a lengthy cast time you must take the Magic Action (that is a different instance every time of the Magic Action) on each turn of the casting.
If the ability says that it takes a Magic Action to cast then it occurs on that turn after you have taken said action (much like how the general consensus for how Divine Intervention works).