Before watching this drama I read the reviews and was shocked to see how so many people gave it a low rating. Some people even gave it below a 5 star so that scared me and I was mentally prepared to watch something truly terrible. However, after I finished watching the whole thing (plus the bonus epilogue), I can say that Journey of Chongzi is not as bad as people make it out to be.

Bad Parts:
• Some characters (like Ting Xue and Sima Miaoyuan) are there just to hate on the female lead. They don't have any other personality except than being jealous of CZ
• There are some plot holes as well
↪ For example, in episode 26 CZ is in ice prison and LYF had put her in a deep sleep along with a barrier to give himself time to master the mirror heart spell to purify her evil aura. Ting Xue, who obviously has a far lower cultivation level than LYF, was able to easily break through the barrier and torture CZ (later episode causing misunderstanding between them) like huh?? LYF didn't even think of putting an alarm of some sort in case someone wants to harm CZ? And he never visited her in those three years while she was in ice prison?? That was really out of character for LYF since he is generally very careful, which is why some points are taken away. Then when he lost his memories because of phoenix tears he shouldn't be able to remember what he used to call her (Chong'er) and instead call her Demon Zi but he called her Chong'er upon seeing her (TZX disguised as her but still because that is before TZX attacked LYF to try to make him remember). A few episodes later he calls her Chong'er again and asked, "Did I call you that before?" Like yes, obviously, because you already called her that a few episodes back when you had that encounter with TZX
• Quite a lot of misunderstandings and the immortal sects being hypocrites, which was annoying

Good Parts:
• LYF's character development and his love for CZ
↪Throughout the drama, LYF believed that he can protect the world while also protecting CZ but this simply made it more difficult for him to do so. Later on he realizes this and was willing to give up his position to be with CZ. He is not afraid to show people that CZ is special to him. In CZ's first life he had no choice but to kill her with his sword to protect Nanhua. During the final battle he chose to do the opposite. He protected and saved her from the demon sword because he couldn't bring himself to kill her again the second time
• The acting of the main leads
↪ Some people think the female lead can't act and complain about her pouty face but I don't have a problem with her face or acting. When the male lead was suffering from heart poison his portrayal of his pain was so convincing that I felt his anguish as well (not literally but you know what I mean)
• CGI and costumes are decent
• Gem side characters, Qin Ke and Mu Yu/Tian Zhixie (TZX)

Conclusion:
Yes, the storyline is not perfect and there are flaws. Some parts of the drama can definitely be better. Despite the flaws and plot holes, it doesn't affect the general understanding of the plot. The storyline is average but the character LYF and some side characters make up for it imo. LYF is not a boring male lead and is actually interesting. He has several layers beneath him. Based on the reviews, I can say that this drama is a hit or miss, you either like it or you don't but definitely give it a try before rejecting the idea completely. You could end up liking it.