I much prefer to trust my glucose meter readings to give me an
accurate indication as to how well I manage my glucose levels. I use a Contour Next which has an option to provide average figures based on my actual tests results over various periods of time up to 90 days, and if I wish I can use this figure to predict my HBA1c with the HbA1c/glucose levels converter on our main diabetes.co.uk website, here:
https://www.diabetes.co.uk/hba1c-to-blood-sugar-level-converter.html
However when I could afford to do so , I found that wearing a Libre sensor gave me the most information as to what exactly was going on with my glucose levels 24/7. It measured interstitial fluid glucose levels, which actually gave lower figures than my meter but most importantly the trends and patterns I saw were the same with both.
HbA1c results, being based on an average over time,(currently 12 months for me) can't distinguish between erratic highs and lows or nice steady/stable figures, so could possibly be quite misleading.