Don't. Computer keyboards are inexpressive. You'll be giving up the ability to modulate note velocity/volume, for starters. Get a cheap MIDI keyboard for a few hundred bucks.
If instead of playing you're more interested in making cool sounds, I'd skip the keyboard completely and download a free DAW like Reaper, Ableton, or FL Studio.
Whichever route you take, the secret is practice. It always is...
Sure, but they can also be a hindrance, and that's been my experience playing music with my computer keyboard. If intervals are all you care about (and it's all you can care about) then I've found it easier to just enter notes with the mouse.
Alternatively, an Akai MPK Mini MK3 costs $100 and gives you twice the range, no limit on simultaneous keypresses, velocity sensitivity, a mod wheel, analog knobs, and velocity sensitive drum pads.
Many synthesizers (especially softsynths) map changes in sound to velocity, that is, how hard you hit the key. Hitting the key harder makes a different sound (e.g. layers more samples) than hitting it softly.
It's pretty bad... This person's obviously talented, but their playing is riddled with mistakes and timing issues. That's not an issue with their playing, it's the constraints of the medium. For example, `[etuG]` is a chord from the video that's impossible to play as it requires a modifier key for 1 of the 4 notes. Plus, the use of modifier keys and the number row for low notes means that the experience no longer maps nicely to a piano. It's effectively learning a bespoke instrument.
This isn't necessarily a problem. As you say, constraints can breed creativity. A good musician should still be able to play great music, but for somebody just learning it's a lot of unnecessary friction.
If instead of playing you're more interested in making cool sounds, I'd skip the keyboard completely and download a free DAW like Reaper, Ableton, or FL Studio.
Whichever route you take, the secret is practice. It always is...