In addition to what you've observed, which is the normal behavior, those settings, dictionaries, etc., are also retained if you uninstall one version of NVDA and then reinstall another.
It is most common these days, under Windows, for most programs to store user-selectable settings, add-ons, etc., under the user's AppData folder, not in the program's install folder, so that a "nuke and pave" for the program is not a "nuke and pave" of everything the user has spent a lot of time and effort setting up. This is particularly handy when the beta versions come out and you may choose to get rid of one and go back to the current released version. It can be done in minutes and with ease.
Brian - Windows 10 Pro, 64-Bit, Version 2004, Build 19041
It’s hard waking up and realizing it’s not always black and white.
~ Kelley Boorn