I'm new to the Forum, so if the question regarding oil dipsticks for Mk8.5 Golf GTIs has been sorted, then I apologise.
I got a new GTI in October and was disappointed to find that there is no dipstick, so I contacted my local VW outlet and ordered one. Part number 06K-115-611-AB cost £20.72 and arrived within 2 days. The plug in the dipstick tube is easily removed with a pair of 'grippy' pliers. Just grasp said plug firmly, then slowly twist and pull. Granted, it did seem to be remarkably unwilling to part company with the tube, but I think that was due to there being a robust sealing ring set into the plug.