While I fully support the concept behind the law, as usual, the law is written in such a way where there may be unintended consequences.
The way the law is written, any website or app that let's you create a profile and post must be federated. This means that any old school forum such as phpBB, MyBB, Vanilla Forums, Simple Machine Forums, etc. are required by law to federate. In theory that sounds good, but you are basically asking a bunch of people to work for free to make their software compatible. Does this also mean that if you can log into your school, gym, employer, non-profit organization, or health care provider and can participate in a discussion, it must be federated, even if those discussions are private? Is that really necessary or desired?
One thing that is really concerning is that they can specify what protocols we are required by law to support. They may force everyone to use AT Protocol or Nostr or some other protocol created by Meta or X that they released to the public. For example, they could force Mastodon to support AT Protocol. If they require any protocol other than ActivityPub, it could kill ActivityPub since new platforms will just implement what is required by law.
The concept is great but this law could hurt the fediverse more than help it, especially if they choose a different protocol.