Dual eSIM Data Switching not "Switching"?

[HyliasChosenOne]

Anyone else experienced this? US Carrier, Unlocked 24 Ultra, roaming on my primary carrier eSIM but have a back up data only eSIM in my current country. 

My primary carrier ocassionally experiences drops in network connectivity, so the secondary data only eSIM is supposed to help there. 

I have the settings set to make it so that when my primary eSIM looses data, the device will switch to the other eSIM for data but either it's not seamless or doesn't work. 

I can confirm if I manually toggle the primary eSIM off, the secondary eSIM does give me data connectivity. It's just the automated switching part that doesn't seem to "kick in" when it's supposed to. 

I thought it would be as smooth as going from say data to WiFi or how WiFi calling features are designed to fast switch between router and celle tower, but so far to me, it's just not. The slightest delay in my connectivity or cellular drop, and I'm waiting more than 3 minutes for the data switch.

I am on the latest software/firmware versions.

My primary eSIM is TMobile roaming in Japan while my back up data only eSIM is uBigi. While roaming, my TMobile eSIM connects to Softbank, my uBigi data only eSIM is connecting to NTT DoCoMo.

Just curious if anyone else is experiencing the slow data switching between eSIMs?

[HyliasChosenOne]

Think I fixed it. Had to reset the APNs.

[Pete-ohki]

How did you reset your APN? Did you have two APNs?

[HyliasChosenOne]

It's the options in the mobile network settings to set them back to default. You have an APN for each sim but I only reset my primary eSIM APN and so far it improved the data switching greatly. My back up data eSIM kicks in near instantly now. The issue seems to have been with the primary eSIM so far.

[Pete-ohki]

Good to know. Thanks! I've been having the same problems with my primary T-Mobile eSIM as well, but in a room of my home despite the fact that I've never had them before adding the second eSIM. In the past, I would either turn both SIMs off & on, or reboot the phone. That would resolve the issue for a few days. Now I use my Wi-Fi connection and let my phone resolve it on its own time. I'm going to try your way the next time I need my data connection without Wi-Fi.

[KasisakL]

S25 Ultra

Wifi calling does work but problem is everytimes I leave hotel and re-enter. Even after wifi connection the wifi calling symbol not appear, I need to restart my phone everytime to activate wifi calling.

Also failure to use function like data switching and backup-calling is noted. No any methods post on internet works. (I use my country esim with turnoff roaming with travel esim that owner is CMlink roaming to KDDI/Softbank in japan)

**All my friend who use iPhone can easily activate this function.