@sphagnum I wouldn't worry about the ratio, just consume enough Calcium and Magnesium foods/supplements to your well-being and tolerance.
Also in the cited study above, the ratio is 2.3, not 2:3, so it's more than two times elemental calcium than magnesium. 2:1 seems to be the recommended ratio in health institutions.
Calcium to Magnesium Ratio Higher Than Optimal Across Age Groups
Objectives
The ratio of calcium to magnesium (Ca: Mg) intake has gained immense attention in recent years, since a ratio above 2:1 has been associated with increased risk of metabolic, inflammatory and cardiovascular disorders. The objective of this study was to assess Ca: Mg ratios across age groups and to determine the relationship between Ca: Mg ratios and markers of inflammation.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6574898
Calcium: magnesium intake ratio and colorectal carcinogenesis, results from the prostate, lung, colorectal, and ovarian cancer screening trial
Conclusion
Higher calcium intake may be related to reduced risks of incident advanced and/or synchronous adenoma and incident distal CRC among subjects with Ca:Mg intake ratios between 1.7 and 2.5.
https://pmc.ncbi.nlm.nih.gov/articles/PMC6889387
Dietary calcium and magnesium intake and risk for incident dementia: The Shanghai Aging Study
Our findings suggest that high dietary intake of Mg is associated with an increased risk of dementia mainly among older adults with low Ca:Mg intake ratios. Proper balance of Ca to Mg in the diet may be critical to the relationship between Mg intake and risk of dementia.
https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/trc2.12362