There are several sound-proof studio facilites in Riga alone.
The largest Riga Motion Picture Studio is a purpose-built facility and it comes with modern production offices, construction workshops, green / blue screens, water tank and wi-fi on all stages.
Alternative / additional warehouse space is also available for bigger scale build.
With construction costs amongst the lowest in Europe, building sets is a viable economic option.

There is also a large 20th century back-lot with standing sets about 50km out of Riga.