Lots of tricks to being successful with Sphag and thus many find bark easier; especially if you water frequently.
Your sphag is way too soaked! You are over watering
Gently remove the sphag around your roots and trim any soggy flat or brown roots.
You have lots of healthy plump green ones.
To prepare your sphag...use a high grade material like New Zealand Sphag which probably will last one year.
Soak it in a solution with some fertilizer or root stimulant like KLN and then wring it out
very firmly so it is more damp than wet.
I prefer some medium perilite in my sphag to create air pockets but that is my preference.
Pack the new sphag in firmly and repot.
Leave about 1/2-3/4 inch from the top of the media to the top of the pot.
I like a clear plastic pot so I can see the roots and the roots can also photosynthesize.
Now the key is to only water like Kelo said when the top is
almost bone dry...when you pinch the top sphag and it begins to crinkle between your fingers.
When you water, you only fill the 1/2 inch space from the top of the media to the top of the pot.
That's it!
Let the water soak in and don't water again until it is
almost bone dry.
Never soak a plant potted in sphag like it is recommended with bark.
Sphag will hold humidity better than bark and if you don't overwater the plant, it will do great.
Another trick: If your plant is pretty large the sphag may inadvertently still hold too much water. So take some styrofoam peanuts and stuff them in/around the bottom core of the plant. This will prevent the "crown rot from the bottom up" syndrome.
Sphag is a nice low maintenance potting material for phals and that is why most of the phals you get are potted in it.
The problem is that many of us
are high maintenance people
Good luck!