Anything you publish in writing is forever, especially with the internet since book burning is now. The only way to say something without anyone ever being able to hold it to you for eternity is to only say things verbally and be sure you're not on security camera or other listening device.

If you're creating an account to be an online spokesperson for your real self, you should absolutely watch what you say, the protocol you use has no bearing on this. Even saying things publicly has the same effect.

If you don't want to have to watch what you say, use pseudonyms. This has never been easier than it is now with the internet, and protocols like nostr actually make this much easier. Sure, every time you speak you create another data point that can help someone figure out who you are. If this isn't an option for you, again, if you're chasing clout you have to be deliberate about wyat you say, period, via any medium you choose.