MtFtM Detransitioner Beard Implants

Since you've recently gone back on testosterone, your facial hair growth should gradually return over time. Typically, it takes a few months for testosterone to start stimulating new hair growth, but the exact timeline varies from person to person. Because you've had laser hair removal and have been on estrogen for three years, it might take a bit longer for the hair follicles to fully recover and produce thicker hair.
As for beard implants, I recommend waiting at least 6 to 12 months to see how much natural growth you regain before considering the procedure. This will give your body enough time to respond to the testosterone, and you'll have a clearer idea of what areas may still need improvement. In the meantime, treatments like minoxidil could potentially help stimulate hair growth, but you should discuss that with your doctor to ensure it's right for you.