You are severely limiting your children.
Developing manual dexterity,
Was there no manual dexterity before tablets then?
The older two play the piano.
They all do a variety of crafts including bead and needlework.
The older two can put a horse’s tack on properly, including fiddly buckles.
The 7 year old can use basic tools to make things from wood, including hammering nails etc.
The girls can do their own hair.
They can plant seeds and move seedlings.
I could go on.
I’d say their manual dexterity is just fine without moving a figure on screen back and forth 400 times a day to beat Joe from down the road’s score.
negotiating the internet safely,
Children shouldn’t be on the internet unsupervised, therefore moot point.
getting support with learning,
Such as? I support them with learning. Oldest is a year ahead of where he should be.
straight forward learning,
Again.....?
learning to coding
I don’t know what coding is. I’m ok.
opportunities to socialise
They socialise every day. Like, actually socialising rather than typing to strangers.
Any more?