International SEO domains: Can I only use primary domain to multiple market with different currency?

[Shawn512]

Primary Market: UK

Store Currency : GBP

Other market: USA/CA/AUS
Using GeoIP and Shopify Payments 

My question:

Option 1: use the primary domain for all the English spoken countries (however they use various currency). No subfolders or subdomains.

Option2: use the subfolders for different countries, even they use same language.

Which is better for SEO please?