You have 2 options. First you can do exactly what you suggested (cancel and re-subscribe) or Second you can use the workaround I posted in the thread above (also below).
But that’s assuming you also own an Apple device like an iPad or iPhone that has the Home App installed on it.
The easiest solution is to cancel and re-subscribe especially if you’re paying the same amount ($8.99).
Here’s the workaround that allows you to still use your HomePods.
Go to settings on your AppleTv.
Select Video and Audio
Select Audio Output
Select TV Speakers as your Default Audio Output
Scroll Down to Temporary Audio Output
By Default your TV Speakers Are selected.
Select your HomePods (Room - whatever you have this set to. Mine is set to “Main Bedroom”)
When you do this TV Speakers gets deselected.
Lastly, select TV speakers again.
Both should now be Checked off.
when you exit back one screen it should now say under Temporary Audio “Main Bedroom + Master” or something along those lines.
Now turn the TV volume all the way down and use the audio from the HomePods.
The Only downside is that you have to control the volume of the HomePods on the App or On the Speakers themselves, but if you don’t mind doing that then this works great.