Does my Toshiba support Apple TV?
Does my Toshiba - 43” Class – LED - 2160p – Smart - 4K UHD TV with HDR – Fire TV Edition
Model:43LF621U19 SKU:6194907 support Apple TV?
[Re-Titled by Moderator]
It doesn't list Toshiba but it does list Fire TV. Since your Toshiba has that built-in, I think you should be able to access Apple TV. I don't have the user manual for your TV or the time to find one online right now but you may want to check that to see how you install apps to your TV. Or if you know how to use Alexa on your new TV, say "Alexa, find the Apple TV app."