No. When you bind a custom domain to a project’s hosting that would be it. You can’t use the identical subdomain for different sites. You can use subdomains like jp.example.com for each site. Just gets expensive and they are all separate and that is hard to manage.
If I had to build large sites with multi-language features I would choose a different solution that natively supports it. Webflow doesn’t. A couple of my favorite others do.
It’s totally possible to do what you mentioned with the href prefix. You just need to create different subdomains and link them to different Webflow projects. The subdomains can be whatever you want: en.yoursite.com ; ca.yoursite.com ; …
Once it’s done, you will need a developer to create the href prefix rule on an external server. Amazon cloud front works very well for this setup. Once it’s done, your projects will be available on the main domain name after the sub directory. Webflow is actually a great tool for this. You can easily manage 2 or 3 websites that have different languages for not so much money. 2*the price of a cms plan is not too expensive.