Maxillaria tenuifolia advice needed

[CZF]

I bought one of these guys about a month ago. It's just a little plant, but had a couple of flowers when I bought it, which have gone now.

I feel like it's not adjusting well and that perhaps the bark medium isn't the best choice for this plant. I understand they like to be moist and get lots of sun, but I'm having trouble finding out what medium it prefers from culture sheets I've looked up.

It came potted in a bark mix, I am wondering if it would do better in sphagnum? I also have a small Lechuza self-watering pot. It has a little wick in the bottom and provides continual moisture from the reservoir to the growing medium.

I was wondering if you guys think I should maybe try to repot with sphagnum in the self-watering pot, if you think it might be a bit happier? I might also move it to a sunnier location, it's currently under a light with my Cattleya's.