I migrated about 5 different Gmail accounts off of Gmail to FastMail and it wasn't too bad. Though it was at least a day of work across all of them. I honestly

I migrated about 5 different Gmail accounts off of Gmail to FastMail and it wasn't too bad. Though it was at least a day of work across all of them. I honestly spent more time trying to wrangle the data in all of the other numerous Google services those accounts had data with.