Have had this discussion with my son who recently passed his test, manual. We both think that a period post test driving a manual will long term be a better way of continuing to become more comfortable with a manual, the risk going straight to an auto is five or so years from now the skills on an manual he acquired may be very diminished, or lost.
I drive both, usually an auto but odd times my wife's car or a van. If the gap going back to a manual is much more than a year or so I feel very rusty (keep forgetting to change gear for this first 20-30 minutes) and it does take time to adjust, and that is after driving for forty year, mainly manuals.
There is a truth re skills re use it or lose it and perservering post test with a manual may be one of these, in addition the need to think about gear changing etc goes so really stops becoming a concern, you drive enough you just don't think about this aspect, it just happens, like walking.
So a couple of years keeping your hand in may be useful in the long term. (If there are manual cars in the long term)