>>529866102
To clarify: Next banner comes in 4 days and will give you 100 pulls for free but only for that banner. Do not use your own pulls yet. After that, 1.5 weeks from now, is the anniversary banner that has very strong units only available on that banner and it also doubles the 3* drop rate.
You don't really need unit variety as a newfag. You can absolutely go through all early game content with what you have now.