If your hba1c is below 48, unmedicated, you have prediabetes, not diabetes anymore.
If your hba1c is below 42 you don't have prediabetes anymore.
However, neither means that your diabetes has gone, it's merely well controlled. Go back to your old way of eating and the diabetes will almost certainly return.
There are several different definitions of Type 2 Diabetes remission used by different organisations and specialists.
Some involve having sequential HbA1C results below 48 while not taking any diabetes medication (though some allow metformin).
My HbA1C figures (on no medication) have been consistently below 42 since November 2020 except for once when I was ill for over 3weeks just before the test, though even that was still below 48. But in the USA my HbA1C levels would still be considered to be pre-diabetic.
Improvement of glucose levels into the normal range can occur in some people living with diabetes, either spontaneously or after medical interventions, and in some cases can persist after withdrawal of glucose-lowering pharmacotherapy. Such sustained improvement may now be occurring more often...
link.springer.com
By that definition I would have been officially in remission, while still having diabetic symptoms. That seems to be a nonsense to me. These definitions are usually drawn up for the benefit of bureaucracies rather than patients.
I would prefer a definition linked to an HbA1c in the traditional "normal" range of 38-42; and achieved while not using glucose-lowering medication for a substantial period of time.