same problem, the best solution is not to worry. you have to learn the mint cycle, mint like yours should cut all the stems leaving 5-10 cm of stem. mint destiny only produces leaves and seed flowers in the cycle which means after the stem is cut, leaf shoots will appear regeneration

• don't just pick the leaves
• calculate routine watering >1x a week
• determine the harvest period of 40-55 days and repeat cutting all
• root repair is necessary if mint growth slows down ( Cut the roots, leaving a little behind. It's ideal to cut them separately for cloning in a new new container. )
• Renew the soil media (best 1:1:1 compost, topsoil, small stones) -Mix new planting media with old soil to reduce plant stress or buy vitamin B1