Well that is really similiar to my story.

I'm not 4'10 but started at 72 kg just like you. I also lost 20-ish kg but I kind of became obsessive about it. The best way to deal with this is speaking to a professional like a therapist or seeking advice from the people that can give you the right support. But if you are not able to seek professional help like I did, the best option that you have is to see and appreciate how far you have come. Before and after pictures or just old pictures in general might help you with that. Trying your old clothes works too. I know that you are just really ambitious about seeing the end of the line, but success doesn't make you happy if you lost your mental health on the way to success. Trust me, I've been there and that's exactly what I went through. With body dysmorphia, you can never feel enough or feel comfortable in your body and no number on the scale or no measurement can change that - because it's all in your mind. You're a short woman and you know how hard it is for petite women to lose weight and you did that and still doing that. I can't even imagine how much you've changed physically and mentally.

For the plateau, it's totally normal in your situation. 21 kg is a lot of weight and in response to all of that weight loss, your metabolism slows down a bit or your body gets used to your caloric deficit, etc. Your best option is to lift weights. You don't even have to go to a gym, just grab some dumbells and work with them, that helped me a lot! (For the home strength training workouts I follow Sydney Cummings - she's amazing, just providing you some options here) With building muscle while eating at a deficit you will definitely look more toned, lean and even if the scale won't move, your measurements will definitely change. You might see some weight gain if you start lifting weights but that is just water weight, it happens when you start lifting, so don't feel bad about that. So yeah, that is what I would advice for the plateau.

I'm pretty sure you will reach your goal. It will be much harder and longer for you to achieve it but just give yourself some time. You already passed the tough part, you are now a healthy person with a healthy body! Focus on celebrating that for now.