It's not 2010 anymore. Client compute is fast. Server compute is slow and expensive. 4G is ubiquitous and 3G is being phased out.

You can send a tiny amount of JS from a CDN and render on the client. You will save money because the server is efficiently serving JSON instead of doing a gazillion calls and string interpolation per request. The user won't notice.

Also, now that the server is responding with JSON it doesn't need to run any JS at all, so you can rewrite the server in an even more efficient language and save even more money.