Being dynamic and swapped countrywise its well possible to err. I think it is way smarter to please shoppers letting them choose the language they wish to use. Forcing a language, based on whatwhatever parameter is not really userfriendly, rather user unfriendly.
Being located in Venezuela, I'm forced to use a VPN frequently. Some US, UK pages won't open. Airtm is blocked by all local ISP also privates.
Cloudflare for most shops I guess it is an overkill. Offering 2 or more languages in shops which fight for each and every customer from just one country is totally unnecesary, IMHO.