It’s a nice air base that will give China reach into the Middle East and it gives them another front against India in a future war.
They can get all that from Pakistan and with a more stable, less fanatical government too.
China will move in and use it as a forward staging area for supply to Iran and an air base to threaten India proper. They will support the Taliban Emirate —they don’t care about how they treat women or girls. They can get along with Brutal despots (like themselves). Just like Putin has his Naval Base and air base in Syria. It makes perfect sense.