In the end It would depend on your goal in each of these markets.
It is a bit of a tricky one. If you build seperate sites for each market, you do run into the chance of some duplicate content, which could damage SEO. (however if they are targeted to different countries you should be ok.
When it comes to the domain each of these are on, it would be recommended to use a unique TLD for each country. So .com for usa, .co.uk for UK and so forth. However, that does come with a slight cost. The alternative is using subdirectories, so that would be .com/uk.
Either way you structure the domains, I would recommend different sites. This will allow you to limit content fully for each region, specifically with ecommerce.
In Webflow, you could build the most complex site, then copy and remove the parts that aren’t required for the less complex ones. Updating will be a bit annoying thought.