The RDA of 1200 mg is for food and supplementation combined with a maximum of 2000 mg in a day (which really isn't recommended, it's just a cautionary warning). Other countries and the Word Health Organization recommend far less for post menopausal women. I'm like you and can generally get to about 650-700 mg of calcium from food. I don't consume dairy so it's challenging and I need to be very thoughtful about it to make sure I get there. I try to use food as supplementation, eating figs with tahini as a snack when I'm running short on my daily calcium. I might take a supplement at the end of the day of about 300 mg but I prefer not to and questions remain as to whether it's really necessary. I take it mostly out of fear that I might not be getting enough. I think RDA guidelines will eventually be revised downward but until then, we just have to figure out what's right for our bodies which is not an easy task. The only thing that's clear is that calcium from food is protective of the bones and heart. Supplementation is questionable and might even cause harm.

Here's a great article on the subject from Harvard Health:
https://www.health.harvard.edu/staying-healthy/how-much-calcium-do-you-really-need

I've been told repeatedly by a variety of professionals (nutritionist, cardiologist, internist) that people with osteoporosis need to get 1,200 mg of calcium a day, preferably from food (which is difficult), supplementing if not. I have heart disease, and due to concerns about calcifications in the arteries, I try to do without supplements, as they can be problematic.