SnoringEarthworm

If you downloaded a malware-infected version, it shouldn't be able to access your accounts.

It remains unknown what the malware that found its way into the official SmartTube APK files can actually do. Thankfully, SmartTube is programmed to only request minimal account permissions and does not ask for any login information directly. Even if you granted the app access to your Google Drive for backup purposes, your Google account and general Google Drive files remain out of the app’s scope of permissions. Permissions regarding control of your YouTube account seem like the only thing that could have easily been exposed to the malware, as far as account access is concerned.

To be safe, factory reset anything you installed it on and double check for Google/YouTube account activity and permissions.

That said, since very little is know about the malware, you should assume the worst. If you use SmartTube and are concerned about your exposure to this malware, you should factory reset any device that had the app installed, especially if you installed or updated the app in November. It would also be a good idea to audit your Google account permissions and your YouTube account activity for anything unusual. Once your devices and account are in order, if you wish to reinstall SmartTube, be sure to only install the latest version through the codes/links above.

Not for users who paid the mobile unlock fee.

What if I’ve already paid the one-time mobile app activation fee?
For users who have already paid a one-time, in-app activation for either our mobile Android or iOS app, an extended trial for the new Remote Watch Pass subscription is available.
(Source: Plex)

They soften the landing with the "extended trial", but anyone who paid the "one-time fee" is finding out what that really meant.

I wouldn't be surprised if a year from now there's an announcement for Plex 2.0 and my lifetime account only applies to legacy Plex.

I don't think that's it.

There were complaints when Netflix started enforcing password sharing rules.

I think the main driver of complaints is "you promised the thing I'm paying for would be X, and now you're changing the deal."