How do I remove this Windows partition?

I wanted to remove the windows bootcamp partition and merge it with macintosh. I went on the Boot Camp Assistant app but the "Install or remove Windows 7 or later version" box wasn't even activated. So I looked up and did something with disk utility like First Aid, Partition, Erase, Restore, Unmount, Mount and everything there is, following some instructions on YouTube. I just decided to go to a local repair shop and they said the partition is corrupted and the only way is to format the entire system. I saw a similar thread here Re: How can I remove this partition? but my diskutil list seems to be a little different from these. Please have a look at the attached screenshots and it would be lovely if I could get some help!