Apache's .htaccess is much worse performance-wise because it checked (and processed if it existed) all .htaccess files in all folders in the path. That is, you opened example.com/some/thing/interesting and apache would check (and possibly process) /docroot/.htaccess, /docroot/some/.htaccess, /docroot/some/thing/.htaccess and /docroot/some/thing/interesting/.htaccess.

Separating api and "front" in different domains does run into CORS issues though. I find it much nicer to reserve myapp.com/api for the API and route that accordingly. Also, you avoid having to juggle an "API_URL" env definiton in your different envs (you can just call /api/whatever, no matter which env you are in).