I'm sorry that you’re being pressured by your parents. First off, are you interested, at all, in going to medical school and becoming a physician in the future? I'm getting the sense that you don't have that full interest because you mentioned potentially going into research and you also don't have the clinical experiences to back up the 'why medicine.' If you're not set on medicine, you need to be upfront with your parents. They are not the ones who are going to be sacrificing their 20s to be in school, they are not the ones that will see patients and have human lives in their hands one day. They are exercising control over your life and career because later on, your financial stability will help them and they can brag about raising a Dr to their relatives/social circle. If this is the case, move out after college and minimize contact/set boundaries with them until they respect your decisions about your own life.
If you are actually interested in becoming a physician but would like a gap year, I would try to get a job and work part-time for now. For example, I'm a senior who's also taking a gap year. I work as a CNA and I'm obtaining clinical experience while getting paid. It's not much money, but it is still something. I'm not in the situation you are in (in fact, completely opposite since my parents were actually hesitant about my decision to go into medicine) but that is just an idea. I'm still a student too so take my words with a grain of salt. Also, to show them how much extracurricular experiences matter, show them Dr. Ryan Grey's Application Renovation episode on the premed student with 99th percentile stats (4.0, 528) who didn’t get in. Since you mention your grades are already low, that would place you at an even bigger disadvantage.
link to the episode: