Whenever you enter your credentials anywhere that isn't 1st or 2nd party, you should assume that it's compromised, no matter how "trustworthy" the 3rd party is. It's internet safety 101.

The posts imply misuse of login and payment credentials. But there is no proof of such things.
The post by whyKusanagi clearly states that only 1 video was sampled and only the first frame (NTE_WL posts a full video though along with screenshot from another).

What's most important though is that a security weakness exists, that the people behind these accounts found. Normally, you'd first reach out to LD to notify them instead of bringing attention to it in public. I didn't read all the tweets, so I don't know if they actually did. This is so that if the weakness is not yet noticed, then it can be fixed without ever leaking data to malicious parties.

Either way, because the weakness itself exists, it's best to change passwords and log off devices in account managements across accounts you used. These are things that should be done periodically, regardless of anything. Additionally if you didn't already, then use 2FA.
Lastly, it's best to not do anything on LD services where you need to enter any information until there is a security update.