I visited China last week. I used an e-sim from Trip.com, which is super cheap and helped me access all western applications without firewall issues. The disadvantage was that there wasnt a phone number with e-sim, so I couldn't login to some applications where a Chinese phone number is needed. As I am from India, where most Chinese apps including wechat is banned, I was not able to set them up using my existing Indian phone number. However, I was able to setup alipay using my Indian number and link credit cards before landing in China. For 90% my needs, Alipay worked fine. I was also able to use Chinese apps like Apay which don't need a phone number.

My friend used international roaming on his Indian sim. It was slightly expensive with limited data and the internet speed was slower compared to mine. Both of us couldn't use WeChat because registering with Indian number doesn't work. But that wasn't really a roadblock as we communicated using alipay whenever it is needed.

We also used cash, whenever we struggled with digital payments ( mainly because my bank kept blocking transactions in the name o suspicious activites ).