I really do not think European countries had "free speech" like it is understood in the US.
After WWII you mostly had state run and controlled TV and radio. And some more freedom in the written press but still most countries mandate Legal deposit [0] sometimes since the Middle Ages. Legal deposit is just the granddaddy of what we understand the Internet is in China.
You could really get in trouble easily.
Then mass media were liberalized and put under the control of big corporations in the 1970-80s what gave the illusion of more freedom.
But the WWW really brought the US free speech standards to the entire developed world in the 90-2000s. This is why people under 50 understand "free speech" according to this standard.
The "you get put in jail because of a meme on Facebook" is really a return to normal after a 20 year pause on the Internet. If you don't fight for it, it will never last.
Starmer, like most leaders in the EU, has an 18% approval rating. He really can't afford free speech for its subjects.
How is age verification and free speech in any case related?
You can solve the problem of age verification without limiting your free speech right. Those two get entangled all the time and it does not make sense.
Non-anonymous free speech is a bit of a red herring. If you say something publicly, especially in this era of mass data, you are perpetually liable to be punished for it at some point in the future. If not by the current government, potentially another. Virtually every country in the world has experienced authoritarianism at one point or another, and there is never a guarantee that it won't again. Saying something publicly tied to your identity is signing up to be imprisoned when an authoritarian who doesn't like what you said seizes power. We have many historical examples of dictators rounding up and executing wide classes of people, so we know this threat model is more than just a hypothetical but rather something that can and does realistically happen at various times and places.
Therefore, in practice, anonymity is the only way to safely express oneself in public. Privacy is the true bastion of the freedom of ideas. This is naturally lost when the means to communicate privately are stripped from us, when every word we've ever said is recorded and tied to our identity. Age verification could possibly theoretically be implemented in a way that does not immediately infringe upon privacy, but you surely know that there is no world in which it will ever be implemented in such a way.
UK and Germany weren't ever good in this department but now worst than ever.
US supposedly good but I wouldn't risk it in practice.
Australia I hear is also quite bad.
Canada and NZ I don't know.
I expect Denmark and Sweden to have somewhat weak free speech laws too.
Norway and Finland I expect to be good.
France I expect to be just slightly better than Germany.
Netherlands and Switzerland, I have no idea.
Czech Republic I think has strong protections.
Italy and Spain and Ireland, I heard mixed reports about.
Poland, Greece, Slovenia, Portugal and other unnamed countries I don't know at all.