Has your HbA1c gone up to the 54 having been lower last time it was checked, or have you not managed to get it under that throughout the whole process of adjusting diet and medications since 2015?
If you want to consider whether dietary changes might help then you could post an average day's diet so we could help to spot if carbs have crept up to maybe more than your body is coping with at those levels. Do you have weight to lose? (Or have you lost any without trying? Either now or when first diagnosed.)
My understanding is that although 54 is not ideal for most people who are type 2, there is not a significant increase in risk of complications compared to an HbA1c of 48, so sometimes that will be set as an individual target by healthcare teams (particularly for older adults as average non-diabetic HbA1c at 70 is a little higher than at 40 anyway - I don't know how old you are, and you don't have to say, but in case you weren't aware of that). So if it stable, that may not be the end of the world, but if you can see a pattern of it creeping up despite the medication then that may suggest that your body is becoming less able to cope and potentially you may need an adjustment to diet or medication at some point.