As far as I know most of the dedicated dealer diagnostics cost them many thousands of pounds and rely on a yearly deal with the manufacturers for the online connection servicing side.
I have been to auctions in the past where people buy the diagnostic equipment from the garage that has gone bust , thinking they will be able to use it, sadly not.
More recently I bought an old Toughbook laptop with touch screen etc. for £40 as it was running Windows 10 (I use Linux) just so that I could install publicly available Fiat diagnostic program (most here use
MES multiecuscan, however one of my vehicles is a Fiat Scudo with a Peugeot engine so had to buy MAXIECU program) a company online called Gendan can give good advice and supply what you may need.
Going back to my point, on the Laptop was a load of Ford Dealer based Diagnostics, I deleted them as without the registered Ford connection it is unusable.