Dropbox desktop app is running, and is uploading files, but not downloading to my Mac

This is a combination of a plea for help and a complaint about the pathetic level of service I have received from Customer Support.

My brand new Macs that are running Sequoia (Mac OS 15.5) are unable to download anything saved to Dropbox. At the moment, Dropbox is open and it is syncing, so my Macs are uploading files and folders when I save them to Dropbox, but I can download nothing. When I double-click on files, the correct app opens, but the file itself does not open. Everything is visible in my Dropbox (name and date, including the correct date now) and when I open the Dropbox App, it opens my Dropbox folder.

Right clicking a file does not give me a menu selection to "Make available offline". Only the Dropbox App icon in a Finder Sidebar has that option, but when I select "Make available offline," I get the message, "Your device could not connect to the server. There may be a problem with the server or network." I don't get this on an old computer that is still connected to Dropbox using the very same network.

I have followed instructions regarding network proxies, firewall, and malware software, and have made sure Dropbox has full disk access. I have tried everything that has been suggested and nothing has helped. I have shut off my machine and rebooted, and that has not helped.

When I signed out of Dropbox as instructed and opened Dropbox and opened it, even though Dropbox is now open, the Dropbox icon no longer appears in my menu bar. 

I explained that fact and asked for my case to be escalated. My request was met with instructions to open the applications folder and open the Dropbox app, in the most remedial terms. I have been using Macs since 1990. I know how to open an application!!! I had already made clear the app was open.

And earlier, when the Dropbox icon was still showing up in the menu bar, I shared screenshots proving that Dropbox was syncing with my Mac but that the cloud icons next to files in Dropbox did not allow for downloading files. I showed that right-clicking does not 

The next recommendation given to me was to uninstall the app according to Windows instructions, which was supremely unhelpful. I have been having a conversation with "Aaron" of Dropbox Support for a week now (with only one email per day in response) and nothing has been resolved. And then I get instructions for a Windows machine when I made it clear in my first message (and subsequent ones and in multiple screenshots) that I'm using a Mac. OMG.  I could scream. 

I tried uninstalling the app the way you usually do so on a Mac, i.e., by dragging it to the trash. (I have not tried using Terminal.) When I drag the app to the trash, I get a message, "The item 'Dropbox.app' can’t be moved to the Trash because it’s open." Again, as I said, the Dropbox icon does not appear in the menu bar of my computer. 

I have sent at least 10-12 screenshots documenting everything and have asked for my case to be escalated and then I get remedial instructions and inapposite instructions. My most recent messages have not been replied to, presumably since it's the weekend.

I need to take my new Mac on a trip with me and I can't access my most important files on it! My older Mac that has a functioning connection is not reliable and I need my new computer to function properly with Dropbox. 

Can anyone help me?