I need to preface this by saying: I don't own a banned Switch.
As such, I cannot be certain that verification by Nintendo servers is needed for the transfer process to succeed.
Now, onto my main point:
I've done two things before, which is (a) akin to sharing/cloning (via official methods) of my user profile.
That means I have the same user profile on both Switches. I can transfer saves (locally) between the Switches (one of the benefits of sharing user profile).
I've done another thing before, which is (b) transferring user profile. This is more permanent than (a), in the sense that the user profile is permanently sent from one Switch, and only resides on the receiving Switch.
Now, why did I mention all of this?
It is to note, that the user save is part of the user profile.
If you used (b), any saves will be transferred over, even if you never played the game on the receiving Switch. (because once again, saves are part of the user profile. If you're transferring the user profile, the save will have to go along)
If you used (a), you can also opt to use the Save Data transfer to transfer between both devices.
Do note you wanna ensure which device has the save you want to keep, cause you wouldn't want to overwrite your save with a blank copy.
[Note: since I have the same user profile on both devices, that means buying the DLC for one effectively means I have both on both devices. Buying the subscription for HOME always means I have it on both devices. After all, these things mentioned follow user profile, not device.
Though sadly, I cannot go online on both devices; I have to go online on one or the other.]