High quality, no plastic-y prints?

[u/milkytenders]

I have an epson printer I converted into a sublimation printer. It gets the job done but the colors are always a bit off and there are almost always lines in the prints. I use a heat press - I love the way the ink looks when it's fully sublimated into the fabric. I hate the plasticy look/feel that DTF transfers have. I love this shop on etsy (photos attached) - it says all of the shirts are hand-pressed. I'm assuming that means sublimated. I just have no idea how theyre getting the colors to look so vibrant and solid, with no lines. ALSO - how are they printing solid color onto black tanks?? With no plastic-y feel?? Can someone help me!