PAYG £10 rolling contract - iphone 15 Pro Use in Canada

[GC58]

I have just switched to a rolling plan- £10 /month and still have £10 credit balance

I have installed an esim and plan to use this for data while in Canada.

I dont want to use the phone for calls / txt/voice messages while away 

As I can not add a Spending Cap is there any way to stop additional charges if i accidentally have the phone set to use the physical O2 sim  for data/ incoming calls - ie can the primary sim accidentally roam onto one of the Canadian networks

Thanks

[Enlli]

You should be able to turn the O2  SIM off on your phone

[MI5]

@GC58 

Just turn off the O2 sim in the phone settings but the worst it will cost you is your £10 credit.