I've had one in 3 days, 1 in a week and one that took nearly a whole month... like everything in thailand, it really depends on your location and the office being used.
I use skyscanner and the majority of the time Agoda is the cheapest so I end up using them a lot, never had an issue and I fly in and out the country for work at least 2 times a month, most months.
Unless you have a valid and current IDP and licence from your home country that indicates and shows you can legally drive a bike, you will need to sit the Thai training and tests. (Not sure how long they take because when I got my Thai licence I had a valid and current IDP). The 5 hours is likely the theory lessons and test.
Brandon is right as always... Non-RE means non immigration reentry, No one is putting non-RE as a non-o retirement, if it was a non-o retirement it would say Non-O, not non-RE, which means non-immigration reentry nothing less and nothing more and is only used as a reference for all non-immigration reentry permits 🤦
Non-RE = non-immigration re-entry. Stamp is likely fine as it even references the actually visa (p-13) but if you truly want to get it changed you need to go back to the airport she stamped in at