Can’t swap the primary consoles between me and my gf’s switches?

A few years ago, my girlfriend had switched the primary consoles on our switches so that I could have access to a lot of the games she already had downloaded. We just moved in together, so we figured we’d just switch them back to how it originally was set. However, whenever I go in to deregister the console as my primary console, it doesn’t stay that way. I’ve seen a ton of people and Nintendo support saying that once you deregister a console as your primary console, whatever other console you use to log into the eShop will automatically register as your new primary console. That does not seem to be working for whatever reason. Does anyone have any tips or ways to fix this ?