VAT Registration for Startups in UAE Wide

SaaS business registered in a UAE free zone, customers are businesses outside UAE. I know exported services can be zero-rated when the conditions are met, and I know zero-rated revenue still counts toward the AED 375k mandatory registration threshold. Where I am less confident is the mechanics of the first registration and the first return when almost everything is zero-rated.

Specifically: whether I register as soon as I cross threshold on zero-rated revenue alone, how the first VAT return reports large zero-rated values without triggering a review, whether I need to change anything in the way I invoice (explicit statement of zero-rating, customer TRN collection, evidence of non-UAE status), and whether there are banks or accounting software configurations that handle this cleanly versus ones that will fight me on it.

Need a specialist who has registered cross-border B2B SaaS companies recently, not a general VAT consultant. Happy to share the current invoicing template and customer geography breakdown on a first call.