Installing GoTo Add-In on Outlook 2016

I am attempting to get the GoTo add-in onto the desktop versions of Outlook 2016, this is both a company issue but I cannot even get it working on my own machine. The OS is Windows 10 Enterprise. It is all up to date as of Jan 10, 2022.

If I go to my Outlook, and go to the 'Add-Ins' section, I click Store and search for "GoTo", it simply does not show up. It does not appear in any search results.

I have also installed it on our Microsoft 365 Admin center, since I have had multiple people asking for it, and the normal exe file we used to use for user's to add it manually seems to have stopped working. Here is how it looks in Microsoft 265, it shows 'assign users', everyone, fixed. But nobody is able to see it. One issue I noticed here is that, our usernames and email addresses are not the same. So my email for example would be lastname-firstname@domain, but the username is just firstname. So if I go here and say "Specific Users" instead of Everyone, I don't see what SHOULD be our email addresses, instead I see usernames followed by the domains. So I don't know if that's a problem as well. 

And as a third option for an attempted install, I go to Outlook, Info, Manage Add-Ins. That takes me to the options for my Outlook online. I see the following. If I click the plus, and then Add from the Office Store, I can see GoTo for Outlook. I click 'get it Now', give permission, hit continue. It says "Taking you to Microsoft 365 to complete this process", and takes me back to my second image, no change is made. 

So no matter what it seems I do, I cannot get the add-in to appear. We used to just download an exe, run it, and the add-in would appear, so honestly the fact they're phasing that out is very frustrating, especially since I can't even seem to find that file anymore. Any direct link to the add-in exe would be appreciated as a stop gap for users who need the integration.