I love pothos and have several different varieties. I enjoy reading about them and know they are listed as “very easy” and “thrive on neglect”. What I have learned is that they can easily be killed by over watering. I learned a lot on this forum and tried the 5:1:1 with a few of my plants but they wilted too quickly. I believe it had more to do with the fact that I have a very busy life and was unable to water them often enough. So I have been using cactus mix and add 50% large diameter perlite. This has seemed to work really well in my home and situation.

And yet I still struggled with pothos!

I would try to propagate in water or in soil and I only got about 50% success. I especially have a hard time trying to propagate any of the variegated varieties like marble queen or manjula and also neon. But even the supposedly "easy "golden pothos has been a struggle for me.

Occasionally it was clearly rot. But sometimes the stem, at the base of the soil would get dark and dry. Not soft
and mushy like I have seen with rot. Sometimes I could cut the stem quite a ways from that area and the stem
may be saved but usually it would all die.

I have been frustrated so have tried to research and read as much about pothos as I can find. I found the below and copied it here. It is from the website often referenced on this forum (plants are the strangest people). I wonder if this is what I have struggled with? I admit that when I want to cut a stem I will just grab a pair of scissors and usually don’t wash or sanitized them between uses. I know that is bad but I don’t even see pests or other things that would make me think any of my plants had any contagious thing.

I have some photos of a recent plant that I think may fit this.

I just wondered if any of the plant experienced folks know anything about this?

Pythium splendens

By far, my most
serious problem with pothos has been a root disease called Pythium splendens,
which causes infected stems to shrivel and go black from base to tip. This has
happened not only to a number of plants from work, which is bad enough, but it
happened to a plant at home that I was actually kind of attached to, a 'Neon'
in a 4-inch pot that had been doing so well for me that I decided to up-pot it.
Almost immediately after the up-potting, it started dying, which was very
depressing. I took cuttings, and we'll see whether anything is salvageable.
Pythium mostly attacks plants that are too wet (I told you overwatering was
bad.), and spreads via splashes of water between plants, or by hands or tools
that have just touched infected soil or plants. My reference book says it can
be fought off with antifungals, but it rarely seems worth bothering to treat
it, since anything I bought to get rid of the fungus would likely cost more
than a new 4-inch plant would. Or just propagating a new plant, which with
pothos is incredibly easy. I personally favor water-rooting, because my success
rate with water is very nearly 100%, and with soil, I only get about 60%
success because Pythium, or something else, gets them before they establish
roots. Water may not be the best thing for the plant once it's transplanted to
soil, but they do at least all survive that way. But that's about the extent of
it.

http://plantsarethestrangestpeople.blogspot.com/2007/11/john-q-public-epipremnum-aureum.html