Any advice for me and my queen pothos?

I got a queen pothos already potted from a connection on the upt Instagram. It started dying almost immediately. So I propagated two separate pieces that I managed to salvage, and they began to prosper almost overnight! So I left them in so the roots could grow. I cleaned the pot, bought new soil, and when the roots were ready, I repotted. Now they’re dying again. What am I doing wrong??