when selecting a transaction it will show a selection bar on the bottom of the screen. this bar allows you to edit the tag for multiple transactions. However, not all categories are shown there, which in turn means you are forced to doing it manually for every item. This can only be done by again deselecting your current selection and then clicking the “three-dots-menu” right of a particular txn, then on edit, then in the side menu (which btw overlays the timestamps on my transactions, when I want to manually add a new one to fix an issue within the data, e.g. missing buy price on a date before my current txn)
maybe the side menu should be relocated to the top or bottom of the page
cheers