I was about to cancel my HBO renewal to transition back to Amazon Prime channels now that's back to make use of my large gift card balance.

However, I noticed the following about the legacy ad-free plan I'm on:

“Legacy customers have access to 4k and Dolby atmos and also stream up to 3 devices at the same time. Whereas the regular ad-free plan will have 1080p resolution and stream on 2 devices at the same time. You keep your Legacy status only when your subscription is auto-renewed. Once the subscription is canceled, you will lose the Legacy plan, and would not get it even if you resubscribe. Currently, there is no date when this 'Legacy' plan will be stopped by Max but they will notify if that changes in the future. ”

So I think I'll stick with this plan for now until they eliminate it before switching back to the Amazon Prime channel method.