Whatever countries you have mentioned have good Indian travelers visiting very often and Airtel and Jio must have some good tie-ups over there. But over here it might take some more time for Indian travelers to explore and networks get feedback and improve.Is Jio really bad abroad?
I had a very good experience (calls, didnt use data) while I as travelling to UK, Ireland and Qatar.
Infact I didnt do any intl roaming plans, just activated int roaming service. And incoming and outgoing calls were Rs2/min. Which was awesome. I could answer all calls with peace of mind. Coverage also wasn't bad.