New user. 1Password not working on Android Firefox on Samsung Tablet

Hey VelvetGlove, welcome to the Forum! We're so happy you've reached out with such details and even provided an update :)

I've looked for a 1PW add-on in case that was needed but the 1Password-X add-on that I've seen a link to on this site has a greyed out install button. The "Classic" 1PW add-on link just leads to a download of an .xpi file which I can find no way of using or installing.

I apologize for the confusion. For Android devices, you will only need to download the https://play.google.com/store/apps/details?id=com.agilebits.onepassword from the Play Store. The add-on you are referring to is specific to desktop devices!

One final observation; having a physical keyboard cover attached to the tablet disables the pop-up keyboard and thus the ability to use 1PW altogether. I believe this may be true of Chrome as well. :-(

Android 11 and Gboard have added support to display Autofill results in the keyboard suggestion strip right above the virtual keyboard. When you have a physical, external keyboard plugged in, the virtual keyboard no longer appears on the screen, so your Autofill results won't be seen either. If you plug out your keyboard, you will be able to see the Autofill results. If you disable Autofill and Autofill previews in 1Password's Autofill settings, leaving only Accessibility on, you will see the Autofill dropdown menu, just like how Autofill appears on your mobile device running Android 9.

That being said, we've had reports of Autofill working successfully while using a physical, external keyboard by switching to another virtual keyboard. Can you try downloading and using SwiftKey instead?