One thing I've found and did a lot of research about.
Last year mine had some sort of disease, white spots on the leaves as the year went on. I read up about it and when the leaves dropped in late autumn, I cleared them up and didn't let them rot into the soil as apparently this can cause more...
Honestly we have a maple acer in the garden, but it's never been potted. Always in soil. It's slowly growing and thriving 3 years later and it's my favourite little tree