Yes I do, I love dahlias, and I’ve got about 20 I think, the first ones are 5 years old now. I just remove the loose dirt, and store the tubers in the garage over the winter on stacked mushroom trays with newspaper so they are separated, I’ve only lost one so far. You can’t let them get frosted though, so they need to be on the inside wall or in a frost free greenhouse.
The main thing is to keep on picking or deadheading to keep the flowers coming. I just use liquid plant food once a week otherwise, as you are doing. I hate cutting them down in the autumn, but I now do it mid October even if the frost hasn’t killed the tops, because it’s a horrible chore on a damp miserable November day.