Is SMT really that complicated?
SMT2 is a sequel to SMT1, SMT3 is in a separate universe and establishes a multiverse that SMT1&2 are a part of, SMT4 and 4A are in their own universe with connections to SMT1&2, SJ has connections to the mainline universe, Persona is its own universe, DeSu 1 is its own universe, DeSu 2 is its own universe, Raidou is its own universe, DDS is its own universe, Soul Hackers is its own universe. . .
It's basically like the Final Fantasy series, except with a mainline of loosely connected games. I guess technically they all take place in the same multiverse, but the mainline games revolve around YHVH or the Great Will in some way, with those entities being multidimensional. It's all very loose outside of 4A.
Something like the Official Zelda Timeline^TM is way harder to understand or guess at because the games were not supposed to be linked (lol). Kingdom Hearts is just a mess because the story is a mess.