A long time ago, LastPass was supported as an app on the Amazon Fire. Very useful. That support was dropped and I coped by sideloading the app.
I speculate that the platform was dropped for a combination of business reasons and possibly the FireOS fell behind Android OS in API support. The same thing happened to a Microsoft app called OneNote.
The new Fire tablets have been announced for release later this month - they will be based on Android 9 ("Pie"). As a part of that announcement, Microsoft will only support Microsoft 365 on it, and bundle it with one of the editions. I notice OneNote is part of that.
So, maybe if OneNote can be supported again (along with the rest of MS Office), it would be feasible to support LastPass again. I am cautiously hopeful.