You should add a playlist of music to the game
for example like this from HOI4:
youtube.com/playlist?list=PLv7cLGQ-wwhsMZ3xIqji1de1G8AKNO-bC
Also when you play as countries, you should play their national anthem (either instrumental or vocal) and if we are talking about 100 player maps, you should put russian instrumental for russian regions and asian for asia etc etc
for example like this from HOI4:
youtube.com/playlist?list=PLv7cLGQ-wwhsMZ3xIqji1de1G8AKNO-bC
Also when you play as countries, you should play their national anthem (either instrumental or vocal) and if we are talking about 100 player maps, you should put russian instrumental for russian regions and asian for asia etc etc