That is the most awful advice — like a parody of good advice. Most of the people reading your code, if it is successful code, will not be familiar with it, and that includes you, in six months or two years from now.

There are two types of variable names.

Very local variables, private variables whose scope is just a few lines like a loop variable, can be very short, often one letter.

But everything else should get an understandable name. I try not to make these "too long" but it's better to have a clear name that is too long than a short one that is obscure.

Very occasionally I will use a shorthand, but if so, it is documented and universal. In my current (hobby) project, I use lamp.instrument.name a huge amount, so it became, officially, iname, but that is literally the only abbreviation in the whole thing. Otherwise, aside from local variables, it's all names like layout_tab_group and MidiScene.