What the Taliban want is the same exact thing they wanted before and after September 11, plausible deniability.
Islamic terrorists, for the most part (ISIS probably being the most prominent exception), like plausible deniability. It’s why Muslim Brotherhood terror groups have “political” and “military” wings. It’s why they conduct the fake divisions between “moderates” and “extremists”. Even Al Qaeda was hesitant about claiming credit for 9/11. Osama bin Laden didn’t make it official until a few years later.
Some of this is Taquiya and operational divisions.
The upshot is that the Taliban are not likely to launch a direct attack on Kabul airport. That isn’t to say that some of their fighters might not assault Americans going there (and they clearly have) or even do worse. As long as there’s some plausible deniability.
ISIS-K plotting attacks works for the Taliban. So do Al Qaeda attacks. Or the Haqqani Network and the various foreign Jihadists.
The Taliban want to play the same game as many Islamic nations, harboring terrorists, yet claiming to know nothing about it, and being unable to control them.
The ideal situation for the Taliban would be for some of their Islamist allies to carry out the attacks, while the Taliban promise to try and control them in exchange for some foreign aid.
Would Biden got along with that? Odds are that he already has.