As the title said. Really not much more to put here.
yes INT is basically all the stat we need with a bit of CON SPR is useless
the usual build is something like 4 int 1 con.
SP Pots are your best SPR points.
INT is a little weird as a lot of spells literally scale 1:1 with your INT but later on spells will hit many, many times and then apply that scaling to each hit. You also get a passive that increase your INT by a certain percentage once you reach a certain Rank Wizard job.
Make sure you invest a good amount into CON as well as the stat is literally amazing for living through things and not having to run in circles while you pray your HP pot cools down before another ranged attack kills you.