All of the sane people are in agreement here. It is very clear that spanking is not working for you and your daughter. In my experience, spanking is not likely to work on any 12 year old. They are old enough that they will rebel... if someone hit you to force you to do something, you would fight back the same way. Your daughter is acting like a normal person.
First of all, I strongly recommend that you get family therapy for you and for your daughter.
Very clearly, the relationship of respect has broken down between you. A therapist will help you build back the respect. Of any advice I could give, this is the most important.
As a child enters into the teen years, the relationship between them and their parents changes... it has to change. The child knows that they have to switch from kid... to adult. Independence is part of this, and experimentation and even rebellion are perfectly normal.
In a healthy family, there is a relationship of respect and trust between the child and the parent that continues through this period. It sounds like this has broken down. You don't build respect and trust through discipline. You build it through communication and consistency.
I have raised two sons (now adults) and now have a preteen daughter. When my preteen screws up, any discipline is mostly symbolic. I take away screen time, but it doesn't need to be much. Because I have a good relationship with my kids... the message (this is unacceptable) is more important in changing their behavior than the punishment.
My daughter and I have a list of things that are issues (i.e. getting up in the morning on time for school and doing homework). Each of these issues comes with a consequence (a loss of screen time). My daughter and I talk a lot about what is fair, and sometimes she wants to change the rules... because I respect her and am willing to negotiate she also respects me and this works pretty well. Each of my sons were different, but the process is the same. You talk through issues, set limits and agree on consequences. Then you stick to them.
The physical fights you are having are not at all helpful and are hurting your relationship with your kid.
Again... a family therapist would likely help a lot.