You can buy phantom weapons in the new shop that comes out around like April or something iirc. That is quite a power boost for new players - all disaster + phantom weapon can almost rival a full SSR grid. Combined with nerfed ults and rags, they'll start farming magna probably within a few months of play if they're active.
EDIT:
You can also buy HSP from that new shop. Limited to 100/month if I'm not misreading, so it'll still take a while, but for those that aren't active enough to join a decent union, you can still unlock Shingen and Morgan eventually.