My first digital camera was a not-quite-4-megapixel Casio that had a Canon lens. I printed a 13" x 19" picture of a shot I took with it in 2002 of the Grand Pacific Glacier (I think it is called) in Alaska. It looks great, even at closer than normal viewing distance. The subject matter helps, I'm sure. Otherwise on my walls are prints I've made on that size paper from shots from my G7X II and before that the S120.
My front room doubles as a guest room or a sitting room. The furniture has a kind of island motif. I decided that before I had guests in last summer I'd print some of the shots I had taken in Hawaii the previous December, to put on the walls in that room. I picked out four pictures that I had posted on line. I could find the original RAW files for three of them to use in preparing the print files. The fourth, it turned out, had been made with my iPhone 6S. (Rather than always syncing the G7X II to the phone for GPS, I'll occasionally just do a shot with the phone, and I can figure out where I was at the time that way.) It's a contrasty picture at a beach, so not the most difficult thing to shoot, but still, it is not obvious that it was made with a phone camera even at that size.
I prefer to have about 300 pixels per inch for inkjet printing, but 170 can give really decent results, as in your 24 x 36 example, more or less. Also, the bigger the print, the farther away you are likely to view it, so you don't need so much resolution. After all, nobody but The Beaver views billboards up close.