My primary audience is based in Bangladesh right now. I am expanding my business with a brand in Canada and USA. I have multiple questions regarding this:
1. Since my primary traffic source will be Google Search, how should I plan the SEO for multiple websites?
2. Should I make USA store the main www.goodybro.com or should I keep the Bangladesh store as www.goodybro.com as it already ranks well for certain keywords? Asking this because I want global audience to land in the USA store as USD is one of the most widely used currencies. However, I'm a little skeptical to change the current Bangladesh store from www.goodybro.com to www.bd.goodybro.com as it is already popular with Bangladeshi audiences.
You can use shopify in any country but can take advantages of shopify payments only in few countries. Shopify Payments are only available for certain geographies and business types but Shopify does support multiple gateways for different countries
With Shopify Payments you're automatically set up to accept all major payment methods as soon as you create your Shopify store
You can rank multiple country stores on shopify by applying Hreflang tags which is used for having similar content in multiple languages.
It can be used by creating a map of your website's language and country's version.
Double check the structure and domain strategy of your entire website with the country's version
Above all i would recommend you to keep your Bangladesh store as www.bd.goodybro.com as it is already popular among the Bangladeshi audiences and would definitely rank well in other countries too.