Two program versions, file associations everywhere

Remove the snap version using the Snap Store or with the command snap remove <packagename>. Indeed, file associations will be removed, However, use Files to restore any file associations that you see lacking: in Files, right-click a file of the type you want to associate, then select "Properties" and set your application as "Default" on the "Open with" tab.

Alternatively, removing both versions then reinstalling the one you want will establish the default associations as defined in the software package. User configuration data are preserved upon removal of a package, so you will not loose customizations that way.