Slow practice I agree with for the beginner, you need to build up finger control and mobility. it will take a little time.
Most digital pianos are keyboards built into a case, the question is what class of keyboard is built into the case of a given model that is affordable to you and what class do you own now. Most inexpensive keyboards don't have piano like action but remind one more of an action similar to what an accordion would have, which is equal weight throughout and light tension to press the keys. Better keyboards and better digital pianos use similar key technology, with similar velocity sensors etc., just the keyboard is portable and may have features making it more stage ready than a full wood cased digital piano. Though many of these types of features are crossing platforms these days. I'm saying that to clear any mis- information you have been given along the way.
Used uprights are available generally pretty inexpensively right out off a graigslist page, probably not too far from home. You have to know what to look for in a used piano and there is annual maintenance cost, as well as moving costs associated with an upright. If I had to compare ownership of the average used upright to a decent digital and spread that out over ten years, I probably wouldn't buy the upright personally. As it stands I own a digital stage piano and a grand piano though. I practice more on the digital ( Kawai MP6) than on my grand piano FWIW. And causes me very little adjustment to switch between the two pianos because the Kawai can be set up , and is set up, to respond very similarly to my grand.