Ben, I like this hymn! It’s a nice departure from the mood and style of the original hymn that we all know very well.
I would echo Lynn’s point about the ending being a modulation. It works very well with the plagal (Amen) cadence at the end, in my opinion.
The main thing that jumped out to me was the V-IV progressions, especially in measures 11-12 and 15-16. This isn’t super common especially in hymnody. I think the one in measures 15-16, for example, could potentially be made stronger by changing the first tenor note in measure 16 to a Mi. See attachment.
Just a thought. Good work, though!