First try calibrating, if issues persist try unplugged the cell, draining the left over and plugging it(simple but you never know), if analogue issues persist then you may need to replace the analogue stick, they don't cost much online and can result in a quick fix, either way you can send the joycons to nintendo as they themselves store no data to show any logs of exploits, if they want the console then restore your original NAND since many logs are stored offline and can show your switch has been running unsigned code at a given time; anyways best of luck fixing it.