seo – Working together with currency, location and language

Currently I have an ecommerce website that runs under WordPress / WooCommerce. Here I want the site to reach different locations, languages ​​and currencies.

Currently I have the following domains structures:

www.domain.com (directed to American speakers worldwide. "Standard Domain".)
en-gb.domain.com (serves UK visitors who speak English.)
fr-gb.domain.com (aimed at visitors from the UK who speak French.)
fr.domain.com (Target audience visitors from France who speak French.)
de-fr.domain.com (aimed at visitors from France who speak English)
en-ca.domain.com (aimed at visitors from Canada who speak English.)
fr-ca.domain.com (aimed at visitors from Canada who speak French.)

Each subdomain targets its & # 39; assigned & # 39; Place and the language. What is the best way to handle currency? Is it just about the following:

www.domain.com (US Dollars)
en-gb.domain.com (pound sterling.)
fr-gb.domain.com (pound sterling.)
fr.domain.com (Euro.)
de-.domain.com (Euro.)
en-ca.domain.com (Canadian Dollars.)
fr-ca.domain.com (Canadian Dollars.)

For example, my concern is which website would be "triggered" for a British person living in France who wants sterling prices. I'm assuming traffic is low, but I'd like to know how people handled it or if it's just a limitation and you just have to deal with it.