The same room has a few potential spots kind of under the level as well. Syndicate medallions are hiding down there pretty often, not sure if the caches can as well

You can link the steam install folder to the standalone files. I did this a couple of years ago and it worked fine, it’s a bit of a hassle though: https://warframe.fandom.com/wiki/User_blog:Rhionhi/How_to_set_up_warframe_to_switch_between_steam_and_stand-alone_clients_with_only_one_install_(For_tennogen_swag,_of_course)

If everything went right, after linking you can run the steam or standalone version at any time and they should only need to download the launcher.

From the sounds of it you don’t really need the standalone install anymore so you could probably just redownload the steam version and use the same login details you do on the standalone though, then delete the standalone when you’re confirmed the steam version is running OK.