Reincorporating Company in US to Fundraise

I'm the co-founder of an Australian pre-seed startup with over 50% of our clientele in the US. We're targeting US investors and plan to reincorporate there in the future.

We've heard mixed advice: some Australian investors suggest we should flip post-term sheet, while others in the US advise flipping before fundraising.

Given the current trends, it seems some VCs might be screening out non-US firms, making US fundraising challenging. Is this a genuine concern? Are US VCs at the pre-seed and Seed stages becoming selective about company incorporation locations?

Would appreciate insights on whether to flip before fundraising or secure a term sheet first.