FWIW I got a Huawei phone (Honor 10 Lite) for under 200 EUR, but much cheaper phones than that are available.
Edit: To be clear this is not to avoid Chinese surveillance. That's unavoidable whatever you do because China is a police state. It's to separate out that surveillance from my contacts and my regular life at home. (I also think it's at least arguable that the Chinese government has a duty to look closely at what foreigners are up to. It's not an argument that I agree with myself very much because it infringes freedom while also making the wrong trade-offs, but given we live in a world of nation states it follows logically from that.)
May be good to make the distinction between the Xinjiang Uyghur Autonomous Region† in the very north-west of China and the rest of China itself. The surveillance, monitoring, detention, "education", and de-radicalisation that are happening in Xinxiang are not to my knowledge representative of the rest of China. It is, of course, very troublesome that this illiberal dragnet exists anywhere in China. We would do well to remember that the crackdown (on the face of it) is a heavy-handed response to multiple Uyghur Muslim terrorist attacks‡ over decades that have claimed the lives of many and injured many more.
While an argument could be made that if any part of China is a police state then all of it is the same could have been said of, for instance, the United Kingdom at the height of the Troubles. At the time the UK deployed watch towers, mass stop and search checkpoints, and harsh anti-terrorism laws that encroached on everyone's freedoms. This was in Northern Ireland but the rest of the UK was relatively unaffected. And nobody at the time that I'm aware of called the UK a police state. The measures were seen as a clumsy response to localised terrorism.
What I'm saying is: yes we know that China is authoritarian, yes we know that it is totalitarian (bar Hong Kong and even that is crumbling…), yes we know China employs a (some would say draconian) social credit scoring system – but it might even still be a stretch to label China in its entirety as a police state when the measures being discussed (installing surveillance apps on phones at security crossings) are localised to one region of ~25 million people out of a country of ~1.4 billion. I'd like to think that if the whole of China was treated the same way there would be an uprising. For the record the ethnic composition of Xinjiang is: 45.84% Uyghur, 40.48% Han, 6.50% Kazakh, 4.51% Hui, 2.67% Other.
Calling WeChat "a kind of malware", what do you mean by this? I would see a miniscule difference between WhatsApp or Facebook Messenger or whatever and WeChat – none of these corps, be they Tencent or Facebook or whoever are cuddly and friendly, they're all out to extract as much revenue and profit from the eyeballs they engage as humanly possible. If you think WeChat is a kind of malware I expect you think the same about WhatsApp and FB Messenger. If you don't, why don't you? Is WeChat actually required in China? I can't find any article to corroborate this claim. Or are you just saying that it's extremely inconvenient to get by without it. One could say the same about Google or Facebook services in the West.
It's effectively totalitarian, special economic zones aside. We've seen what happens if they try to stir the pot politically. Their relative "freedom" is exercised with a guillotine permanently above their heads and no legal rights.
Everyone is surveilled across every arena of life.
And if you really think people only disappear in Xinjiang, look at the history (and continuing present) of human rights or democracy activists. [0]
[0] https://www.hrw.org/news/2019/05/30/human-rights-activism-po...