I've got a mobile phone holder from a brand called Osomount which uses a strange sticky material that will stick to almost anything but certainly a "grained" dashboard.

When it ceases to stick you wash it under plain water and it becomes sticky again - I'm very impressed with it. I've seen sheets of this sticky stuff on Ebay but goodness knows what they're called - I found this link though

https://www.ebay.co.uk/itm/Universal...frcectupt=true

you could try a sheet of that between your sucker and the dashboard