Is there any way to block adding apps to only one device if you have multiple devices that are linked? The "unlink" description seems as though the device will be removed and that is not what we want to do.
If you want all your Roku devices to remain linked, the only option available would be to enable/require PIN before Channels/apps can be installed.
To enable a PIN, go to your online dashboard at https://my.roku.com/account or https://www.roku.com/ and login to your Roku account.
Then select "PIN Preference" [Update]. Select "Require a PIN to make purchases and add channels."
(https://support.roku.com/article/220128567)
The PIN applies to the entire Roku account, and all Rokus linked to it. I don't know of a way to preferentially add a PIN restriction to individual Rokus on the same account.
@Aaron81- Your Roku channel apps are added to your Roku ACCOUNT. All Rokus linked to the same account will have all the same channels. (Exception: older Rokus not supported by some channels will not receive those channels.) Add/remove a channel on one Roku, you add/remove on all Rokus linked to that account.
If you want a different selection of channels on different Rokus, link them to different Roku accounts (i.e. each account having its own separate email address and own list of channels).