As mentioned, this is a user-to-user forum made public for us users by WD to discuss WD products and related issues.
Without going any deeper on this topic, I want to say that making the WD products or apps work with any product like Fire TV is not WD’s responsibility. This is like saying their products need to work with Apple products the way you may want them to. You are not “geeky” enough to fully understand what is going on here.
Kodi is not an official app for the Fire TV; Amazon does not approve it for their app store except in one instance, that app is called MrMC and it can be downloaded from the Amazon app store. It contains a special version of Kodi built-in that meets all the requirements of Amazon (such as it cannot be configured to do some of the “bad things” Kodi can be made to do, such as connect to media piracy websites_)
Kodi is an appropriate app for what you want to do with photos, but it is your responsibility to install and use it correctly.
Also a Smart TV is not going to solve your problem, so save your money on that. Devices like FireTV, Roku, and apps like Kodi can make your current TV “smart”.
If you have a Roku, it has a special Roku app that enables you to view your phone and tablet photos and videos directly on your TV. This is how I can see them, because I also have a Roku as well as a FireTV/with Kodi.installed.
Don’t blame WD (or any other company) for the problems and frustrations you are experiencing. Basically, this is all I am going to say on this anymore.