I wish you weren't focussing your case from the US 'freedom of speech' vs UK 'foreign government is trying to silence a U.S-based forum' angle. It feels Trump-ish. I am writing from the UK. But I kind of understand why you might want to do so from the perspective of a more likely positive outcome from a legal perspective.
For me it is a moral argument. It is a case of 'people' in the UK - including the BBC, Ofcom and, sadly, even the Samaritans, as well as the 'general public' and bereaved loved ones, misunderstanding what the suicidal mind is like and what it sometimes needs.
I feel your case would be more convincing, on a human level, if it were more aligned to the argument given by some of your supporters on X (a platform I generally dislike). For example: 'This forum supported me during my darkest time — when no UK mental health service was accessible. It kept me alive. The state of mental health services in the UK is shocking. That is what needs addressing, not this' and: 'I still don't understand how we haven't evolved past hasty generalization. Everyone acts like children, wanting to hate faster than just trying to understand or critically think. There were maybe a few people who promoted suicide and self harm, and they're generalizing us all.'
It is complicated, nuanced, dark, not where 'normal' people go.
The UK is (relatively) a good place. It has got it wrong in this instance in my opinion. I don't want to use a VPN. I have no shame in or fear of what I am saying.
I would like to know who the woman in Merton (London) is who has been arrested 'on suspicion of intentionally doing an act capable of encouraging or assisting the suicide of another' [BBC} is, and who her lawyers are.