You can probably do impressionistic realism in any medium. Which is gonna achieve the look you want or feel the most intuitive is up to you. Oils and acrylics are fun, but so is working digitally. You may also want to forget the painting for now and just work on your drawing skills. If you can render a portrait with a certain level of abstraction in graphite, you're already halfway there.
Best advice is just practice and experiment. There is no right or wrong way to go about it. If something isn't working for you, make changes until you find something that does.
I'd say traditional. It will surprise you with effects that come naturally to the medium you're using. If you want something more like the second one anyways.
The first one does use the raw digital look surprisingly well, but even so, you're going to have to work a bit harder to get the spontaneous feel from digital brushes that gives the approach it's energy. If you do have a lot of experience using digital however, maybe you won't notice it so much.
Try charcoal and willow sticks.
Pastels might be good too, but I can't speak for them, as I get along with them about as well as oil and water mix together.
Using acrylics or oils to get a tangible texture is always super fun.
For one of my painting classes in high school we had to chose a Van Gogh piece to recreate, and I decided on this one. I made the colors brighter and used a pallet knife to do the entire thing... and it ended up being one of my favorite pieces to come out of the entire class. The texture of it is so awesome and fun and spontaneous and ever so slightly random. I love it. I like touching it with my eyes AND with my hands.
The only downside is that it needs to be dusted all the time since dust get lodged in all that texture!
If you don't have the traditional foundation and media practice, especially when it comes to abstract art...
making digital will be extremely difficult, and most likely very unsuccessful.
Start with graphite drawings, dap into some charcoal if you want. Then go with acrylics. They're a great way to learn colour mixing and painting without the fuss and technical skill that comes with oils and watercolours.
I love drawing in graphite. This is probubly my main medium. Me and charcoals go together like oil and water.
Acrylics I havent really had much time to enjoy, but I hope to start using them much more!
Oils and Watercolors I really like the look and texture of, but I just cant really get a grasp of them yet haha.