Thank you, laticauda. When I check the soil to water, it is usually very dry on top. Usually I feel through the bottom holes, too, and while it isn't "dusty dry," it is dry. What could still be happening is water retention right at the roots due to this weird soil. The bark I have in there is rather chunky like the coco coir above, and there is a fair amount of perlite, but I what I suspect is peat is the problem. There isn't much of it, but what is there just seems to just cling to the plant roots. That could be a good thing or a bad thing--I mean, the nursery used peat without issues, right? I should have sifted it all through a colander or something before I put it in, but it honestly didn't look that bad out of the package. Never buying bagged soil again, unless it's fast-draining bonsai mix. Thanks for everyone's help. Maybe the better looking plants will pull through this at least. I pulled out the one very droopy plant and the roots I trimmed weeks ago have hardly budged in growth. :(

So it isn't a philodendron? There was no growth on the stems that were in the glass of water. The leaves were slowly browning and falling off one by one. I think that was before it was dug up though. I can't quite remember the timeline of things.......The browning may have happened after the digging, I'm sorry, I just can't quite remember when I started becoming concerned about it. When they started browning, I remember thinking I maybe shouldn't burn incense by it anymore because maybe that was affecting it. The plant is directly to the left of a south facing patio door but the shades are drawn a lot of the day to conserve energy. You're saying I should probably move it to a more lit place assuming it comes back to life? Also, I should re-pot the plant in new soil? Any particular soil I should use?

Pinch the growing tip to force it to send out more vines. Or wrap the vine back on itself tacking some of the nodes to blank areas of the soil. After a few years you will be cutting off excess vines to give away or throw on the compost heap. Take care of it and it will be everywhere. https://philodendronplant.com/heartleaf-philodendron-grow-and-care-tips/

Look up some information on wet stick propagation. It may be better off sitting on moist sphagnum moss in a humidity dome or ziploc baggie. I think it can grow another leaf but it will take some time. Also, I got some cuttings from brandtianum last year and they put out all tiny leaves for a while. I finally got one normal-sized leaf after about 5 months. I have the cuttings under a cloche.