Q.2 Acer plants growing and developing completely differently
I have 2 plants which have and are being treated in exactly the same way – one is flourishing and the other is looking very very sad…have tried swapping locations etc but nothing seems to work – how can I help the one plant more please??

Certified GKH Gardening Expert
If that container does not have a way to drain out extra water, then that will be the cause. Overwatering leads to fungal infections, and since they are both in the same container, the other one is likely not far behind to look the same way.
Make sure that these dry out very well before allowing extra water back in. Make sure that it doesn't get left in the rain or get watered when it is still wet.
Next you will have to go about treating the issue.
Apply a handful of DOLOMITIC lime, and WETTABLE sulfur to both containers to treat the sick one, and prevent the same from happening to the one that is still healthy.
You should start to see recovery within a few weeks of treatment.
This article will help you to care for these trees: https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maples-in-containers.htm