Have you heard of Heino Eller ?

He is an Estonian composer who taught the likes of Tubin and Pärt. I was not aware of him until I heard his 3 symphonies on a radio broadcast.

These are strong works, superbly orchestrated and with a genuine sense of drama.

Unsurprisingly, he has a good wikipedia page which is linked to another page from the Estonian music center here.

His symphonies have not been recorded so let me know if you are interested. This is a major composer.