You are bang on. It appears to have been going on for years with no solution. From my reading elsewhere people have been able to play around with their tv settings in the past (aspect ratios etc) and have cobbled together a solution. The problem with that is they had to change it every time for Zwift as that affected other things which they had to change the ratios back for. More modern TVs like the one I have just bought apparently don’t have the settings to change as much (as you shouldn’t need to).
It’s not the biggest problem in the world but it is annoying. The consensus from people far more tech savvy than me appears to be that it is a Zwift app problem but this has never been confirmed or denied by Zwift ( although I can not confirm if it has been mentioned by Zwift or not). What pisses me off the most was my previous tv did the same but it was an older one and I thought it wasn’t properly compatible with the newer Apple TV 4K. I bought a brand new TV, a 50” 4K LED thinking that it would be brilliant. It’s not. Same problem.
Don’t know if it’s worth me dropping support a line although they’ll be immersed in their TDF stuff right now.
UPDATE: I went ahead and contacted support so I’ll let you know what they say if they reply.
UPDATE 2: Zwift support got back to me within an hour ( big kudos for that) and here is what they say:
“ Thanks for reaching out to us here at Zwift! I’m sorry you have a problem with your image on your Apple TV. I will be happy to help.
There are two ways to adjust screen ratio. The first will be through your tv, by going into your menu and adjusting, either the resolution or screen ratio . The second will be through your Apple TV.
Apple TV’s Settings menu enables you to choose the best screen resolution and refresh rate for your television, although this method requires some trial and error.
Your Apple TV has an Auto setting that dynamically adjusts resolution as you stream content. If this setting doesn’t work well enough, you can cycle through the other resolution settings using the Apple Remote during playback.
I hope this has been able to fix the screen ratio issue, please get back to me with any other concerns and issues!”
I’ll give it a shot and get back with the results.