I'm unhappy with my Nintendo Network ID (by name)
And I have purchases in the EShop.
Since you can't change the name, you have to create a new NNID account, but is there any way that the purchases will be transferred? Or are they stored on the system?
(What would happen if I delete the account or the EShop closes in 10 years, then I have no access to the games?)
Unfortunately, you can't change the name or transfer any purchases to another NNID.
The purchases are stored on the ID and available on your system as long as the NNID is stored on your system.
If you delete the NNID, the purchases will be deleted from your system, and then they will be permanently gone with the ID.
If the eshop closes you can still use the software as long as it is installed on your system, so you can still use it, but you should not uninstall it, otherwise they will be gone when the eshop is closed.