People told me I should reach out to potential postdoc supervisors about 6-12 months before I finish my PhD and stay in touch with them.

But what should I say when I email them? Should I just ask them if they plan to take on a new postdoc this year? But they don't have an ad for the recruitment, which clearly shows that they don't have any money at the moment for a new postdoc (if they had the money, then they would post an ad for sure!). So asking if they are recruiting a postdoc sounds like a stupid question. And if they do have an ad, then I should just submit an application - what's the point in reaching out to them before I submit an application?

And what other things can I say in my emails to them? Maybe I should introduce myself? But if they don't have money for a new postdoc, it should be meaningless to introduce myself I think?

I really don't understand why people keep telling to start early and reach out to the academics I'm interested in. I don't think I have anything to say to them.

I think you need to get out of this shithole as soon as possible! This PI tricked you, and later they will probably continue to do harm to you. The sooner you get out of there, the better you will protect yourself from further harm.
And you don't need to hide anything from any potential PI when you look for a new position. It's not your fault, so just tell them the truth. Once you tell them the true reason behind your move, they'll see you're a true scientist and an ambitious young researcher.

This professor didn't give you any details, but if you're curious you can ask them for clarification.
This pandemic is really annoying and has fucked up the whole academia. I've heard many universities in the UK, US, and Australia have laid off some teaching staff and researchers. Many US universities have stopped recruiting new tenure-track academics. The main reason is lack of money. I guess your situation also has something to do with money.

I'm mainly asking about the situation in the UK. But if you're in another country, you can also talk about the situation in your area.
From June, many labs in universities have reopened. But recently, many areas have gone into local lockdown. I'd like to learn how the new lockdowns have affected your lab work.

I haven't been on here for a long time. If OP is still here, I just want to say, hey, OP, you're not alone!
I've seen so many things like this. Many supervisors are biased. So are departmental heads. When things happen, their bias make them choose to take one side, and treat the other side like rubbish. And when you ask for clarifications, they will never give you any clarifications. When they're biased, they are biased. They wouldn't admit it. They never acknowledge they've done anything wrong. They have power over you and they could do anything they want. You just can't get any justice from them. If you resist, they will take it further and make more people go against you. They're just like that. That's the true face of academia. I've never seen a PhD student who successfully resists the evilness from the people who have power.
If you want to get the university involved, you could try, but don't expect too much. The involvement of the university will be time-consuming and take away lots of energy from you. Lower your expectation. Also, try and talk to the potential university and see if that university can help.

Thanks cucaracha. That's helpful.
I think it's difficult for me to stay sane if I need to find out every supplier's name for each sample we've bought and to draw a picture of the experimental setup...

I'm writing my thesis now, but I wonder which part they usually focus on? Do they read the results and discussion chapters more careful than the things before them? Will they read my experimental methods carefully? I mean, do I have to dig out every detail of my experiments and write them down? Is it worth it? I hope I don't need to spend too much time writing every detail. If they don't read it carefully, then I shouldn't waste my time write a very detailed thesis.

I'm writing my thesis now, but I wonder which part they usually focus on? Do they read the results and discussion chapters more careful than the things before them? Will they read my experimental methods carefully? I mean, do I have to dig out every detail of my experiments and write them down? Is it worth it? I hope I don't need to spend too much time writing every detail. If they don't read it carefully, then I shouldn't waste my time write a very detailed thesis.

I don't think there's anything wrong with mentioning your dog's name before your supervisor's, if the dog has been more helpful than the supervisor.

When I'm reading papers, I notice that some authors show their ORCID, but most authors don't.
Is showing ORCID a requirement by some journals? Or always optional?
I think all authors should provide readers with their ORCID so that readers can know who they are, where they are now, and how to contact them. But why do most authors not show their ORCID? I hope journals will press all authors to provide their ORCID

Oh thanks abababa, this is very informative.
So now it's clear: the corresponding author of this paper doesn't need to upload this manuscript to his institution's repository.
But I don't quite understand this: 'It's generally better for them to have a small number of staff returning high-quality outputs'. Does it mean that the uni may choose not to return some academics' outputs just because they're deemed as non top quality? Is this allowed? I thought all academics' should be counted.

I've heard some German universities do that. But it seems that UK, US & French unis don't save master's dissertations online.
My master's dissertation isn't online :( Apparently my uni (in the UK) can't be arsed to do it.
I think it's good to put it online if you think your master's research is of high quality. If you're unsure, just ask your supervisor. If your supervisor says it's better not to put it online because the research quality isn't high, then don't do it.