Plese read under the Minimum Income Requirements title here https://citizenremote.com/visas/serbia/

So that’s pretty expensive for just a year-long visa. Even Spain has lighter salary expectations for DNV applicants of €2520 and Spain is more comfortable by far.

Romania has minim salary requirements of €3700/mo. Croatia - €2300/mo. For an extended stay in Serbia you should also make at least $3500/mo. Moreover, Croatia at summer time is pretty expensive if you plan to live by the beach.