Can anybody advise me what is allowed by the First Amendment

[Dame of Mercia]

Hi, in the UK somebody recently had to pay a fine because of some words exchanged with some paramedics who had come to attend to a neighbour. The person had also put a note on the ambulance saying that it shouldn't have been posted across her drive. It was on an online news site and some people from the USA had enquired whether there was a restriction on freedom of speech in the UK. As I say it was for being stroppy (obstreperous) with the paramedics that the fine was imposed not for the note but it got me wondering what the First Amendment does allow. There are restrictions on hate speech in the UK.

I'm not going to go down that rabbit hole again but some months ago I posted about a spiteful conspiracy theory I had come across on the weird side of YouTube and I did wonder why nobody mentioned therein had sued for slander or libel (though I suppose it's difficult with 50 different states all with their own different laws). Is it hard to prove defamation in the USA because of the First Amendment?

[Dame of Mercia]

I've found a few online videos by attorneys about the First Amendment so I have a better idea now.