I am need to VPN back to home town (Hong Kong) for accessing corporate server while I am travelling. Once I VPN, then the "intellegence" iOS 26 switched off my Travel SIM (physical SIM for local data access) and switched all voice and data to Smartone.hk, which is my home SIM (eSIM). Man! I was immediately disconnected from VPN and of coz, disconnected from internet as well.

I had contacted Apple Genius in Hong Kong. They were first heard of this problem. Genius reported my case to Apple engineering team to seek for help. A week later, Apple Genius contacted me that and said there is NO solution for this. The Apple Engineer is suggested me NOT to use VPN !!! ... WHAT!?? What is a nonsense suggestion. I do prefer this Apple Engineer suggest me to change to use Android phone instead of iPhone.
The latest iOS 26.2 is not help. This kind of SIM switch is even more frequent. >___<