eSIM not connecting to 4G networks

Hi.

I have an IPhone 17 Pro (26.2 iOS).

The problem I’m facing is that, after I restart my phone, everything works fine when it comes to mobile data. It connects to the 5G network and it keeps itself like that for a few days.

Problem is… after a couple of days, I get the “E” on the network signal and I don’t get the 5G ever again unless I restart my phone.

What I’ve tried:

• contacting the eSIM provider: they say everything is fine on their end, and they can see that, when my phone connects to a 2G network, it doesn’t try to connect to a 4G again
• Airplane mode ON for 1 minute and then OFF again, does not solve
• Restarting the iPhone is the only thing that temporarily fixes the issue

Is this a known issue? It’s really a bummer having to restart the phone every single week just to get proper mobile data! If anyone knows how to permanently fix this, I would appreciate it.