Up or Down?

The founder of Islam supposedly went to something called Sidrat al-Muntaha.

S 53:13-14 He saw him in another descent, At Sidrat al-Muntaha.

"[D]escent". That is down. But Sidrat al-Muntaha is supposed to be up.

Anas narrated that the Messenger of Allah said:

“While I was traveling through Paradise, a river appeared before me whose banks had tents of pearl. I said to the angel: ‘What is this?’ He said: ‘This is Al-Kauthar, which Allah has granted you.’” He said: “Then he put his hand in the clay, and removed musk from it, then I was raised up to Sidrat Al-Muntaha so I saw a magnificent light at it.”

https://sunnah.com/tirmidhi:3360

It is narrated on the authority of Abdullah (b. Umar) that when the Messenger of Allah (ﷺ) was taken for the Night journey, he was taken to Sidrat-ul-Muntaha, which is situated on the sixth heaven, where terminates everything that ascends from the earth and is held there, and where terminates every- thing that descends from above it and is held there. (It is with reference to this that) Allah said:

" When that which covers covered the lote-tree" (al-Qur'an, Iiii. 16). He (the narrator) said: (It was) gold moths. He (the narrator further) said: The Messenger of Allah (ﷺ) was given three (things): he was given five prayers, be was given the concluding verses of Sura al-Baqara, and remission of serious Sins for those among his Ummah who associate not anything with Allah

https://sunnah.com/muslim:173