No, Airalo will NOT work on Galaxy A models, at all!!
Get the S model, Airalo works on these S models.
Last year a friend cruised with us and he had the A model and Airalo didn't work and we found out the A models do not support eSims.
This year, he swapped his phone with a S model and we were able to load Airalo on his new phone and get it to work. We fly out in 3 days' time!
May I add, my DH, DS, his GF, other friends and myself included, use Airalo a lot and they work good! We are able to reuse the eSims when we revisit the country or region. Just buy and activate the top ups.
When you're on the airplane and on airplane mode, turn off the active esim first and turn on the next esim (make sure you've named each esim accordingly, e.g. Home, USA, North America, Europe, Portugal, etc). This way, when you land and turn off the airplane mode, the esim kicks in (usually a minute or 2) and you're good to go.
We are in Bermuda, BTW. Our ISP/Cell offers unlimited roaming at $13 per day - no thanks!! - and we need to make sure the Home esim and data are completely turned off before we land in foreign country or we get incurred the first day's roaming charge!