You got yourself an old worship space. Certainly the place was designed with the best acoustics achievable at the time. Lots of seating, too. And with luck there’s plenty of parking. Does that say theater to you? It does to me!
And this is not as sacrilegious as it seems. Before it was a secular entertainment, drama was an act of worship. The statue of Apollo, god of art, is set up this theater, the Roman theater at Orange in Provence, and performances began with prayers and sacrifice.
So that’s a natural direction for modern churches, and many go that way. Here is The Old Church Concert Hall, in downtown Portland, Oregon. It was built in 1882, one of the oldest churches in town, and is a magnificent example of Carpenter Gothic that is listed on the National Register of Historic Places. Unfortunately there aren’t enough Presbyterians downtown now to keep it alive as a worship space. In the 1960s, to prevent demolition, a coalition of concerned citizens converted it into a concert hall, and it’s been happily in use ever since for chamber music, lunchtime concerts, and other events.