Apple tv app not syncing across multiple devices/platforms

I’ve had this problem for ages, but it’s gotten worse in the last couple of years. The ‘up next’ and ‘keep watching’ section of the Apple TV app isn’t the same across three Apple TV devices, my iPad, my iPhone, and my iMac. They each have different content, as if they each stopped tracking at a different point in time. It’s driving me nuts. Yes, I’ve done all of the steps below:

1. Verify that both use the same Apple ID account.
2. Verify that both are set to sync this information through iCloud:
   1. On Mac TV app: Settings﹥Playback﹥☑︎ Use Viewing History
   2. On Apple TV: Settings﹥Apps﹥TV app﹥Use Play History﹥On

It’s my account on each device (difficult to miss my mug on the user icon), and yes, I’ve got the settings correct. Each device is updated to the most current version of their OS. I’ve signed out of each device multiple times, rebooted, turned settings off and on, to no avail. Separately, my contact list also doesn’t sync between my phone, iPad, and iMac and never has for years and years and many multiple devices, even those where I started from scratch. Is this likely to be a glitch in iCloud? I really don’t know if there’s anything else I can do, but it’s insane when I go to a device and can’t find the tracking for something that I was just watching in another room of the house on another device. It’s not horrible, if I just remember to open the other app, like Prime Video or whichever app I’ve been using for streaming, but it’s awful when it’s something I’m watching on Apple TV itself - in that case, I have to find the program and then the episode and fast forward to where I think I was before stopping in another room. This is nuts. What else can I try? I’m not a newbie - I worked in tech, with Apple, for years. But I’m at a dead end.