After reading so many blogs out there and nothing of them worked for me to hibernate Linux Mint 21.2, I randomly found a video on YouTube that worked for me. I'm sharing it here so that it can help others too and me in future if I forget it.
- First: this blog post is the one he followed in the video.
- The video - first part: 56 seconds long.
- The video - second part: 3 minutes and 45 seconds long.
- The video - third part: 38 seconds long.
- A link from the video description: StackExchange answer.