I've imported some apps code and drivers code, but I can't install because my install user app button is missing. I've rebooted the hub, reloaded the chrome browser, tried the edge browser.
I've searched the community and support docs and came up empty.
Just to ask the stupid question, are you sure that there is a user app to install? Open the Apps Code selection in the upper left corner “hamburger” menu, see if any User Apps are listed to be installed. Perhaps you loaded apps into the Drivers Code by mistake. Some of us have made that mistake at least once.
Edit: Apps Code in the left sidebar. Didn’t realize from my glance at your picture that you weren’t just browsing to the Hub’s IP, but were using the app. I only access the admin stuff by browsing to the Hub IP. You might try that, too.