Amazon's FireTV experience is pretty bad. Even as someone who pays for Prime, it's hard to escape the "ad carousel" interface when you just want to watch TV. That being said , I still use mine regularly for one reason; sideloading. You can install YouTube clients with SponsorBlock and ad-skipping built in. You can download Steam's streaming client and connect a controller, or load up Kodi with SFTP streaming from you…
I've recently (last week-ish) started to get the ads, too (I'm in France). But they don't seem to have made their way in the actual Prime Video app. I actually always used the "app" because I much preferred the organization.