i tried the 3HK before, what i want to say is very useful, i also have flexiroam
you can try flexiroam, the global plan bit pricey, but you can buy local plan for the traveling country earlier to get cheaper price
for example, traveling to thailand, 500MB@USD0.90 for 3 days if purchase 60days earlier if not mistaken

my flexiroam esim can rebind to new phone, previously i tie on my Xs, after change to 11 pro, i just scan again on my 11 pro, no issue
somehow maxis esim require a new qr code for my 11 pro

wonder why some can make it reuse (i tested my flexiroam recently oversea with my 11 pro, seems reuse is fine)

with iOS 14 or above
transfer eSIM from old phone to new phone can be done, no need new profile qr code
https://support.apple.com/en-us/HT210655#:~...14%20or%20later.