Firstly, do you have an official bug tracker? If you do it's so well hidden I can't find it and if you don't why don't you? I have several issues with your Kindle Fire 7 (5th Generation) with Fire OS 18.104.22.168
1) The menu items in the Kindle Book store appear twice. This is clearly a software defect. I have tried (as advised by kindle support) turning it on and off again (restarting the device) which made exactly no difference. I have tried restoring the settings to factory defaults which made exactly no difference. I was sent a replacement kindle because your support had no idea what was going on and determined my original Kindle was faulty. (I'm sorry but the only thing that was faulty was the software on the kindle and the support advice.) I finally managed to correct the problem by re-flashing the firmware using adb sideload. I should not as a user have to do this.
2) Having taken receipt of the replacement device, it appears to be a Kindle for Kids device. Once again, after an extremely frustrating "chat" with kindle support, they advised me that the adult and children versions were exactly the same. THIS IS NOT TRUE! whilst the hardware may well be the same, the firmware is so utterly unconfigurable as to make the device unusable. I can not set it up without agreeing to be billed for the Kids Unlimited service (of which 12 months is included) - there is no cancel functionality to get out of this. Additionally, every time the settings are reset, I get the same issue. The 'offers' are almost entirely directed to Kids. This behaviour is a defect in the software. You might say it's by design, but I'm sorry I refuse to accept this. The device is MINE and I should be able to use it as I see fit, not how YOU want me to use it.
3) There is no way of removing preinstalled apps from the home screen - again, this is a software defect. I'm not talking about being able to uninstall the app, just remove it from the home screen. I do not want to see Amazon FreeTime, or Fire For Kids. I don't want to use them now and will NEVER want to use them. They are quite literally a complete waste of space to me as I'd like to put apps that I do use there. All I want to do, is remove them from the home screen
In short, your launcher is not fit for purpose. Amazon describe this as a Tablet. Every tablet I have used since the original iPad is configurable in this way - except of course those branded Amazon Kindle. The Kindle Fire 7 (5th Generation) is being mis-described - it is not a tablet at all. it is an e-reader which has been crippled by the shoddy software installed on it. Amazon clearly do not understand what a tablet is, or should be.
It is very clear to me now that Fire OS is nothing more than an expensive (the customers' expense) advert for Amazon. You clearly have no interest in what your customers actually want to do with the device, or how your customers might want to use the device. I will be very likely to get a real tablet next time - one that I can configure in the way I want, not the way the manufacturer wants.