Using dual SIM whilst abroad

[fallon]

Using s22 ultra with dual SIM. Backup calling enabled for using seconds Sims data for calling on primary SIM when signals poor.

My question is, my primary SIM will work abroad etc but cost me a fortune, whereas my data only SIM is free to use in Australia.

Is there anyway I can keep using my primary number but permanently use the seconds Sims data (WiFi calling) for the calls so then it's free? Or is it a case of you'd have to use the second SIM completely and disable the first one to avoid charges?

So I want dual Sims, primary SIM will cost me £2 a day to use, second SIM is free but data only. Wanted to use primary number using the second Sims free data 

[Tourbillon De La Vie]

Disable roaming for sim1 and use sim 2 for everything. You will still be able to receive calls and messages on sim 1. However you'll be charged for any call answered or voice mail left for that number. I turn off voice mail when abroad and do not answer calls

[fallon]

SIM 2 will be a data only SIM..so if I turn roaming of on priority SIM 1, will that use SIM 2 for backup calling? Priority SIM is £2 a day to use abroad. But even without that I've never been charged for accepting calls on my UK main SIM in Australia. Think it was probably on WiFi calling though

[fallon]

How would you call a number in that country tho? You'd have to use your priority sim wouldn't you?