The biggest mistake people make with travel eSIMs isn't technical. It's timing. They wait until they're at the gate, phone at 12%, boarding call already announced, to install something for the first time. Do it days earlier instead, and the whole thing becomes boring in the best way.
Boring is the goal here. A ritual you do the same way every trip, days ahead of departure, is worth far more than a clever trick you have to remember correctly under pressure at a departure gate.
Install while it's still free
Once you install an eSIM, it sits in your settings without costing anything until it's actually used for data. There's no reason to wait. Buy your plan and install it the week before you travel, on your own Wi-Fi, with time to fix anything that goes wrong. If the install fails for any reason, you've got days to sort it, not the ten minutes before boarding.