I'm thinking about quitting my PhD program and seeking advice
I have a few thoughts. First, since you have completed comps and the dissertation proposal, there should not be any reason that you have to remain in state to finish your degree. At my university, many students finalize their dissertations while living out of state. Perhaps moving back near your fiance and family would alleviate some of the pressure that you are feeling. The downside of moving is that you would have to finance the remainder of your degree. If you do not have a large number of dissertation hours required, this may be feasible. Also, if you tell your chair that you will be moving out of state after the spring semester, he would know that he is going to lose his GA even if you do not graduate.
Dissertations are hard. All of our ideas and work are constantly being judged. It is common to feel loneliness, despair, stress, frustration,and the list goes on... I believe that the current pandemic has heightened all of these emotions making the dissertation burden even greater. I think it is also common to begin to hate the field in which you are completing the dissertation and to question if you will ever be able to use your future degree.
Ultimately whether or not to continue is your decision. Your parents will love you no matter what you decide. Will you be disappointed in yourself if you leave the program? Will you always question how life might have been different if you completed the degree? These are questions that I would ask myself.
Wishing you all the best as you move forward.