I stayed in Serbia for a month and I liked it more than I thought I would. Cities are loud and friendly. People love music and coffee. Summers get hot and sunny. Winters can be cold and snowy. Most travellers enjoy the river beaches in Belgrade. I once played beach volleyball at Ada Ciganlija and met a developer who moved here for the cheap rent.
For digital nomads this is nice. Rent and food are easy on the wallet. Cafes have good Wi Fi and cities have fast internet. There are a few coworking spaces and regular meetups. Novi Sad feels calmer and full of festivals. Belgrade has wild nights and live music. You can hike in nearby mountains or visit old monasteries on a weekend.
For some this will be amazing. For others, no sea might be a deal breaker. But if you want lively cafés, low costs and a growing nomad crowd, give Serbia a try.