If you want an HC carpet, you need injected CO₂. You will also need a decent amount of light, but the CO₂ is the key, along with good water flow and distribution.
If you go for a minimalist look like in your picture, then distributing CO₂ to the carpet plants is not too difficult because you don’t have lots of stem plants and hardscape obstructing the flow.
If you do go for a minimalist look, I’d recommend using as much external equipment as possible to keep the tank as visually simple as possible. That probably means an external filter and external CO₂ diffuser. I’m not a fan of hang-on-back (“HOB”) filters because they often restrict your options for positioning the inflow and outflow.
For my nano tank, I also opted for an external Hydor heater. The problem with that is that they’re only available in a minimum of 200 Watt power, which would quickly kill a nano tank if it stuck “on”. So I also use a temperature controller so that if either that or the heater sticks on, the other should switch off the power to the heater. I personally think this arrangement is a wise precaution for any smaller tank.
I also made my own spray bar out of a length of clear plastic rod, into which I drilled small holes. It was important to me that the spray bar is colourless (hence less visible), unlike the typical Eheim ones.
Personally I hate tanks that look like chemistry sets, with loads of tubing, glassware and equipment everywhere. Some stuff you can’t avoid because it has to be inside the tank, such as a drop checker.