This is one of the chorale preludes from the Orgelbüchlein Project. It has a note on the score "After Brahms," and indeed I think it's more Brahms than Brahms himself. It was first performed by Tom Winpenny at St Alban's Cathedral in 2017.
Christian von Blohn (b 1963) is director of music at St Ingbert in the diocese of Speyer and teaches at the Saarbrücken Music Academy.