I used [quipqiup](https://quipqiup.com/) to solve the challenge,and added the numbers because the page didn't show them in the plain text.

**The flag is: picoCTF{N6R4M_4N41Y515_15_73D10U5_702F03FC}**

Original writeup (https://github.com/DoomHackCTF/WriteUps/tree/main/picoCTF2022/Crypto/substitution2).