It's years of skill and many different learned things to arrive on a curated outcome like this personal site, which is the point. Don't try to get there today, but maybe make your own site that's the best you can build with what you know.

And honestly, if you do want to jump into this, there's nothing better than just to start. Use something like codepen and start playing with CSS & CSS animations. Try replicating some of the text animations (there'll be lots of examples on the internet) and go from there. After CSS animations (which will get you 80% of the way), would be helpful to explore composition & color theory (from a design perspective, studying and replicating examples is good to pick up skill and find your "design voice"). From there, the sky's the limit.

The main illustration is done in the Ligne Claire[0] comic book style made famous by Herge in Tintin (and common in French and Belgian comic book).

[0]: https://en.wikipedia.org/wiki/Ligne_claire

He's definitely going for the style of Tintin comics, the so-called ligne claire. The books I see which claim to teach that style are in French, and out of print: the 2-volume L'atelier de la bande dessinée avec Hergé. But, read the comics anyway, they are fun.

ctrlpaint.com is a great resource. The tutorials are comprehensive and free.

I also highly recommend the book Drawing on the Right Side of the Brain by Betty Edwards.

Unfortunately there’s no hacks to learn draining overnight. Deliberate practice is the only way. Doodling in the margins of your notes during boring meetings is a great way to get reps in.