I am Chinese located in Shanghai/China, and so is my girlfriend. My girlfriend has been working in foreign companies since 2016, and I have been keeping using English as much as possible since 2014. My master's thesis (2016, ECNU) is about EFL writing, and I am developing a vocabulary acquisition application for language learners. What's more, we are both preparing for our next IELTS exams. I mean my girlfriend and I are the
Chinese people who are eager to practice English.
The fact is that the method you mentioned/recommended is not that practical as it may sound.
In our 4-year relationship, my girlfriend and I have tried to communicate in English on WeChat(think of it as a Chinese version of WhatsApp for those who are not familiar with it), but quickly we switched back to Chinese. The reason was that the communication became more and more like a burden. Learning or practicing is not a happy or easy process, though it may lead to happiness and convenience. Communication should be as convenient and happy as possible, and hence English as a barrier should not block our happy bonding experience.
We have never tried to talk to each other in English even when we were joined by a native Anglophone in a conversation. Just because English widened our bonding/distance, and it's awkward. Imagine that a British man is having a classic British meal in a traditional British restaurant in London, and all diners there are British. The awkwardness may just be like the gentleman and only that gentleman is trying to practice using chopsticks. The learning goal does not match well with the learning environment, the learning content, the learner's characteristics, and the support provided.
Let me describe another experience of mine where I tried to practice English with a group of Chinese eager to learn English in a WeChat group.
I once organized an 'English corner' based on a WeChat group where most members are normal Chinese adults (not students) like me. Every morning, I tried my best to initiate an intermittent discussion on a topic such as favorite food etc., but what I saw in the evening in that group with about 50 members were all my own words with a few good morning greetings by others. An ex-colleague of mine once advertised her language learning project in the Philippines in the group in English, and we spotted many obvious errors in her messages. I encouraged them to speak in English by telling them that 'do not be so scared and hesitant to make mistakes when learning a new language because native speakers grew up making countless mistakes', but what I saw was just silence. Most of them cannot even construct a complete sentence correctly and dare not to attempt. Maybe we are more intolerant to each other for the fossilized errors.
I have never seen English practicing in any WeChat group for English learners, and I don't know if it is a culture issue specific in China. And I am also wondering if it would be appropriate for me to ask a new question on how people with the same native language and the same target language can practice with each other.
I just wrote above in a first narrative to explain why I usually don't practice English with another Chinese person or a group of Chinese. I am trying my best to continue searching for an appropriate method, and once I have some more expertise on this topic I will rewrite this answer. Hope this helps.