Putting one line in airplane mode on a dual sim iPhone

I have seen this topic several times online but I have not yet found the solution. I spend at least half the year abroad, and whenever I get a spam call (which is feels like a million times every day) and I am not on wifi calling I get charged $10/day from AT&T. Before I got the dual sim iPhone, I would carry two phones and I would put my AT&T iPhone on airplane mode and I would still get calls, text messages, iMessages, and facetime calls when I had wifi. I got the dual sim phone so I no longer had to carry two phones. I just would like to put my AT&T line in airplane mode (this is the eSim line) and to have the other line working like normal.

I can disable the AT&T line but that means my messages and calls of all sorts will not go through on wifi like they did in airplane mode.

I will note that it works fine in airplane mode now, but that puts my second line in airplane mode and then I cannot get calls on that line.

Any help would be very much appreciated.