Try OpenBoard .
You can resize the keyboard in the settings up to 150%.
It was rated on NBTV, who really hype up privacy and Graphene, for its respect for your privacy. I use it without issue.
How do I make the keyboard bigger?
Dumdum I didn't realise it existed. I've now installed it, thank you, and the immediate bonus is having proper spelling, whereas Open board would use US spelling despite being set for the UK.
mmmm Not forgetting any word that has "our" in it. It's like loaning your drill and it is returned with the chuck key missing
commodore64 I agree that FUTO works very well, and it integrates well with Heliboard.
Both heliboard and FUTO work without network permission.
jacobb indeed it does, hence the satisfactory comment. But in OpenBoard, UK means "mostly UK, if we can be bothered"