What are you trying to do?
If you are traveling to China and want to bypass the great firewall, you can try good VPN services like Express, Nord, Astrill, VPN.ac, etc. Most time they will work unless for sensitive times.
Ref:
https://www.tipsforchina.com/mobile/using-vpn-in-china-2019-blog-performance-testing.html
Read the above and you will know that the Chinese authority has the know how to block all traditional VPN vendors if needed. But usually they do not do that and will let the minority people be able to use the VPN services (minority means millions of people).
Data roaming is easier if you are on a short trip.
If you need to stay in China for a long time, you may consider paying for SSR/V2Ray/Wireguard providers along with the traditional VPN vendors to have access even in sensitive times.
If you want to access China Geo-blocked contents like Tencent Video and iQiyi, and for that single purposes only (not for privacy and security), go for Transocks 穿梭 or SpeedIn 快帆. Traditional more well-known VPN vendors are not good for this purpose.