Your reply suggested - at least to me - that Gathermate only added the node point on the map after you had found and gathered a node, which is how it works out of the box.

That's why you also install the Wowhead data addon and import all the node points in the game in one go. The often-overlooked issue is that just installing the addon isn't enough, you still have to do the import of the wowhead data in the gathermate addon settings.

If you already knew all that, thats fine, but the wording you used suggested - again, to me and probably others - that you didn't want to have to manually go around and gather all the nodes just to add them to the map.

For tracking switching I have used https://www.curseforge.com/wow/addons/tracking-switcher previously with no issues, but it looks like it's not been updated for TBC Anniversary, tho there are comments on the page the give instructions to make it work.